System for cardiac resuscitation

[0001] This application is a divisional application of U.S. patent application Ser. No. 10/460,458, filed Jun. 11, 2003, now U.S. Pat. No. 7,277,752.

[0002] Sudden death from cardiac causes, often due to heart rhythm abnormalities such as ventricular fibrillation (VF) and ventricular tachycardia (VT), claims approximately 225,000 persons annually in the United States (1999 Heart and Stroke Statistical Update—Dallas: American Heart Association, 1998) or approximately one per 1,000 population per year.

[0003] Nationwide, only two to five percent of those who suffer an out-of-hospital cardiac arrest are saved (New England Journal of Medicine 2000; Vol. 343: Pgs. 1259-1260). In grid-locked cities like New York City, analysis of the Emergency Medical Service/Fire Department data has shown that less than 1% survive the ordeal. Because of the abysmal survival rate, the first arrest is almost always the last.

[0004] Cardiac arrest is the abrupt cessation of the heart's mechanical function leading to loss of consciousness and the rapidly progressing sequence of heart and brain deterioration, irreversible heart and brain damage, and death. This cessation of mechanical function during an arrest is often caused by a sudden chaotic deterioration in the heart rhythm referred to as ventricular fibrillation (VF) or by the sudden onset of a very rapid and mechanically ineffectual rhythm called ventricular tachycardia (VT). In either case, the heart's normal function can usually be restored by a prompt and properly administered electrical shock to the chest, generally referred to as defibrillation, or by application of synchronized electrical pacing signals.

[0005] It has been estimated that once an arrest has occurred the mortality rate increases by 10% per minute until definitive therapy commences. If treatment has not yet commenced ten minutes into a cardiac arrest, there is little likelihood of recovery. The evidence that the response time has a profound influence on the rate of successful resuscitation comes from two types of analysis: a) comparisons among studies in which the response times were different; and b) comparisons within studies, where the results of a short response time are compared to a longer response time, within the same population. The discussion of comparisons among studies follows.

[0006] Data from New York City and Chicago illustrate the poor results associated with a long response time. There are an estimated 7,000 incidents of cardiac arrest each year in New York City alone. Emergency Medical Service figures during a five year period—1994-1999—revealed that a total of only 168 patients were successfully resuscitated. The average EMS response time, from the time the service was summoned, was reported to be seven minutes. Based on the 10% per minute mortality estimate, one would expect a 70% mortality for a 7 minute response time. The EMS survival figures are much worse than would be expected based on the ten percent per minute mortality estimate. The reason may be that the time from the event onset until actual defibrillation is substantially longer than the 7 minute EMS dispatch and transit interval. This prolongation includes delays: a) from the moment of onset of arrest until EMS is called (referred to below as the “pre-call” interval); and b) from the time of EMS arrival until life-saving therapy is begun (referred to below as the “pre-shock” interval). Even if the sum of these delays is only three minutes, the expected resuscitation rate plunges to a negligible value, and is consistent with the observed very low survival rate. In Chicago (population over 3 million [linear interpolation of 1980 and 1990 census data]; area 228 square miles) the reported results, though slightly better than in New York City, are poor nevertheless. Becker et al. report that 91.4% of patients were dead on arrival at the hospital; 6.8% died in the hospital and 1.8% were discharged alive (New England Journal of Medicine 1993; Vol. 329: Pgs. 600-606). The response time, defined as the interval from the 911 call to the arrival of the ambulance (referred to below as the “call-to-arrival” interval) ranged from 1 to 22 minutes; the median was 6 minutes.

[0007] Improved response times are obtained by so called “code teams” in a hospital setting. An analysis of data from Kaye et al. showed that 9.5% of 210 hospitalized patients who suffered a cardiac arrest survived to leave the hospital (Circulation 1999; Vol. 100: Abstract 1645, page I-314). Eisenberg indicates that survival rates for inpatient cardiac arrests have been reported to range from 0 to 29% (New England Journal of Medicine 2001; Vol. 344: Pgs. 1304-1313). The higher survival rates are attributable to faster reaction times in the hospital environment.

[0008] Still better results are reported from King County, Wash., where the emergency response system is unusually sophisticated. Sweeny describes a 30% survival to discharge figure (Annals of Emergency Medicine 1998; Vol. 31: Pgs. 234-240) for this group. Similar results are reported from Rochester, Minn. (1993 population 76,865; area 32.6 square miles); White et al. report the results of 158 cardiac arrests between 1990 and 1995. An analysis of their data, in which the survival to hospital discharge is calculated for all arrest victims shows the value to be 26%. They make a more meticulous effort than some prior investigators to define and measure their response time, and they used the “call-to-shock” interval. Analysis of their data shows the value to be 6.0 minutes. (The aforementioned Chicago data was based on a 6 minute “call-to-arrival” interval. The call-to-shock interval is the sum of the call-to-arrival interval plus the pre-shock interval.)

[0009] Gambling casinos are an ideal locale for the analysis of the relationship between response time and outcome for two reasons: a) because of the ultra-high level of scrutiny, the time of onset of arrest can be known accurately; and b) because of the high level of stress for some patrons, the arrest rate is enhanced. Valenzuela et al. report on a program in which casino security officers where trained and equipped to rapidly defibrillate arrest victims (New England Journal of Medicine 2000; Vol. 343: Pgs. 1206-1209). There were 148 patients who suffered a casino cardiac arrest in 10 casinos in Nevada and Mississippi during the years 1997-1999. Fifty six victims (38%) were resuscitated and survived to hospital discharge. The interval from “collapse-to-shock” was 4.4 minutes. It represents a very short response time since it is the sum of: (a) the call-to-arrival interval (used in the Chicago study), plus (b) the pre-shock interval, plus (c) the pre-call interval. (The 6 minute Minnesota result was based on call-to-shock, i.e. (a) plus (b).) The interval from collapse to paramedic arrival was 9.8 minutes, which (without early defibrillation by the security officers) would be expected to result in a negligible survival rate.

[0010] The two keys to high arrest survival rates are a short interval from onset of arrest until provision of defibrillator shock, and the presence or rapid arrival of expert medical personnel at the arrest site. The compelling nature of the relationship between response time and success rate is further demonstrated by comparisons within studies.

[0011] The Rochester study divided victims with ventricular fibrillation (84 of the 158 arrests) into two groups: one group resuscitated by the police, whose call-to-shock time was a mean of 5.6 minutes, and one resuscitated by paramedics, whose call-to-shock time was 6.3 minutes. The fraction of a minute difference in arrival time impacted the survival rate. In the police group, 58% survived to hospital discharge; in the paramedic group with the slightly delayed arrival time, 43% survived to hospital discharge. (These survival values are larger than the previously mentioned 26% because that value included other arrest victims [i.e., victims with asystole and pulseless electrical activity] who are far less likely to be resuscitated than victims with VF.)

[0012] The casino data also gives firm support to the relationship between quick shock and hospital survival. Again, looking only at the VF victims, of those who received their first shock in less than three minutes, 74% (26 of 35) survived to hospital discharge, whereas only 49% (27 of 55) who were shocked after three minutes survived to hospital discharge.

[0013] The best results, in terms of resuscitation rate, occur in the hospital cardiac electrophysiology testing laboratory. Here, during the conduct of arrhythmia evaluations (referred to as electrophysiologic studies) in high risk patients, life-threatening VT and VF are frequently encountered. However, because of the presence of trained highly experienced arrhythmia physicians and nurses at the procedure, and because of the very short response time (time from onset of VF until time of shock is usually less than 15 seconds), the resuscitation rate is significantly greater than 99%.

[0014] The near 100% resuscitation rate in the electrophysiology laboratory represents an ideal that is not likely to be reproduced outside of the laboratory because:

[0015] a) the arrests in such a laboratory are all due to VT and VF, not asystole or pulseless electrical activity;

[0016] b) these arrests are artificially induced; hence, they are primary electrical disturbances, not electrical disturbances secondary to some other process, such as the sudden blockage of a coronary artery;

[0017] c) the response time is extremely short; and

[0018] d) doctors and nurses specializing in heart rhythm treatment are present at the procedure.

[0019] Nevertheless, the electrophysiology laboratory data does show there is nothing about VF per se that implies its irreversibility. As long as the response time is very short and the VF is not secondary to a sudden catastrophic structural problem (such as the abrupt blockage of an artery within the heart), we can expect a very high success rate. This concept is supported by the resuscitation results in patients with implantable cardioverter-defibrillators, which automatically detect and terminate VT or VF. Their response times and success rates, for spontaneously occurring VT and VF are comparable to those of the electrophysiology laboratory. The high success rate for very prompt termination of VF was confirmed in an entirely different setting. Page et al. report initial termination of VF in 13 of 15 (87%) patients who were treated as part of an effort to provide commercial airliners with defibrillators (New England Journal of Medicine 2000; Vol. 343: Pgs. 1210-1216).

[0020] As the time until shock increases, two types of events seem to occur which markedly reduce the chance of success. First, there is evidence that the longer the response time, the smaller is the fraction of patients actually found to have ventricular fibrillation. In other words, it may well be that in the moments immediately after an out-of-hospital arrest, the fraction of patients with VT or VF among all arrest victims is high; and that as the minutes go by, that fraction decreases. In the casino study, with its very short response time, 71% of victims had VF. In the Rochester study, with its intermediate response time, 53% had VF. In the Chicago study, with its long response time (since the 6 minute reported response time included only the call-to-arrival component), 22% had VF (calculated from their data). The fraction of victims with VF is important because among arrest causes, VF is far more likely to be treatable than either asystole or pulseless electrical activity. (In the Minnesota study there were 74 non-VF victims; and in the casino study there were 43; none of these non-VF victims were resuscitated.)

[0021] The second deleterious event which occurs very quickly during VF is the onset of irreversible mechanical damage to the heart muscle. Once such damage occurs, the chance of survival to hospital discharge plummets. The Minnesota study analyzed this by looking at a predictor of survival that they called “ROSC,” restoration of spontaneous circulation. ROSC was defined as present when either no cardiopulmonary resuscitation (CPR), or less than one minute of CPR was required. Victims with ROSC also did not require any medication to support their blood pressure. ROSC was a powerful predictor of survival to hospital discharge. Twenty seven of 28 victims (96%) with ROSC survived to hospital discharge; 14 of 56 without ROSC survived to discharge. The police with their 0.7 minute earlier arrival time had a much higher ROSC rate (42%) than did the paramedics (28%).

[0022] Automatic external defibrillators or AEDs were used by the police in the Minnesota study. They were used in the airline study and by the casino security officers. These AEDs are intended for use by minimally trained personnel. AED electrodes, which must be properly placed in contact with a cardiac victim's chest wall, allow the device to analyze the electrocardiogram (ECG) signals of a cardiac victim. Based on the ECG signal information which it receives, the AED automatically applies a high defibrillation voltage to these electrodes when its algorithm detects VT or VF. The decision to shock or not to shock, and the magnitude of the voltage application, are determined by circuitry within the device.

[0023] A number of systems are known which provide automatic external defibrillation. Equipment of this type is currently distributed by Medtronic Physio-Control, Philips and Cardiac Science, and may be purchased at a cost of about $2,500-$3,000 per unit. This equipment is now intended to be made available at places such as government buildings, casinos, airports, office buildings and sports arenas, and to be carried upon public modes of transportation such as commercial airliners. There is an increasing effort to have them carried aboard police cruisers.

[0024] The advantage of AEDs is that they allow a decreased response time by empowering non-medical people who can arrive sooner than paramedics to treat a cardiac arrest. In the Minnesota study, most police cars carried AEDs; they arrived sooner than the paramedics; and they had better results. In the casino study, cited above, security officers defibrillated with AEDs at a mean of 4.4 minutes after victim collapse; the paramedics arrived at a mean of 9.8 minutes after collapse.

[0025] On an airliner, the chance of arrest survival without on-board treatment is nil. The cardiac arrest survival rate in Boston increased from 16% to 24% when the number of AEDs was increased from 85 to 185 and all 1650 firefighters were trained to use AEDs and to perform cardiopulmonary resuscitation (Circulation 1998; Vol. 97: Pgs. 1321-1324).

[0026] Although AEDs have improved survival by decreasing response time they cannot be considered to be the ultimate solution because they lack certain important advantages that a highly trained medical professional possesses. The transfer of a responsibility, which traditionally lies within the domain of the medical profession, to the AED and its operator results in or fails to completely address seven classes of potential problems:

[0027] a) the limitation of proper AED performance to conditions addressed by its algorithm;

[0028] b) the necessity of assuring the proper electrical interface between the AED and the victim;

[0029] c) the persistence of delays not entirely circumvented by the AED;

[0030] d) the problem of CPR administration;

[0031] e) the problem of potential AED malfunction;

[0032] f) the aggravation of problems (b) through (e) in the event that the user of the AED is untrained or inadequately trained; and

[0033] g) the potential aggravation of any of problems (b) through (f) by the absence of a highly experienced professional taking charge of the emergency scene.

[0034] The seven classes of problems (a) through (g) will now be addressed and discussed in detail.

[0035] First, an AED relies on its internal artificial intelligence to make a decision about whether to provide a proper high voltage response for termination of a life threatening heart rhythm. The device must be programmed to anticipate as many situations as possible, and it must be programmed to function appropriately during each of those situations, in order for the automated response to have the intended effect of resuscitating the cardiac victim. The use of the device thus decouples the victim's treatment from the intelligence and judgment of a medical professional who normally administers external defibrillation. This usurpation of the medical professional's role by a machine and its minimally trained or untrained operator may, at times, result in incorrect or delayed responses in just those critical moments which can make the difference between life and death.

[0036] AEDs, no matter how complex their algorithms are or will become, are not able to perform properly under conditions which are not explicitly addressed by their algorithms. For example, Kanz et al. (Circulation 1999; Vol. 100: Abstract 1641, Page I-313) showed that AED-based rhythm diagnosis was often incorrect in the setting of substantial external electromagnetic interference. When 12 units were evaluated in railway stations, sensitivity ranged from 80 to 100%, and specificity ranged from 38 to 100%. In power stations, the performance was even worse, with both sensitivity and specificity ranging from 0 to 100%.

[0037] Other important issues which may not be addressed by an algorithm include the management of the victim who is fully or partially conscious with a tachycardia, and the management of a victim with an implantable cardioverter-defibrillator or ICD. Still other issues beyond the scope of current algorithms involve advanced management considerations such as post-defibrillation treatment.

[0038] Sophisticated EMTs will not benefit by carrying AEDs since they would be likely to know far more than the information on which an AED algorithm is based. However, a defibrillator device which provides the EMT with an immediately available medical expert consultant could improve arrest outcome.

[0039] The second limitation of AEDs relates to electrode positioning. It is known that correct defibrillator pad positioning and application is very important for successful defibrillation. Errors in positioning and poor electrical contact are not uncommon among inexperienced operators. AEDs do not actively guide the user in appropriate pad placement and application (other than by the provision of a diagram). Nor can they detect or correct for inappropriate positioning and application, once it has occurred. A defibrillator device which could provide such guidance would be highly desirable. Although highly sophisticated electronic means could provide such guidance, a human observer with means for observing pad placement could easily accomplish this.

[0040] Third, even partially trained AED users can not be expected to match the skills of a highly trained medical professional. For example, the casino study showed that 0.9 minutes elapsed from the time of defibrillator attachment until the time of first shock. A medical professional could accomplish this action in a fraction of this time. A defibrillator device which lets a remote ultra-sophisticated medical professional deliver the shock would therefore save time, when compared with the casino scenario.

[0041] Fourth, an AED does not coach an untrained bystander in the performance of CPR. Although CPR is not required in arrests of short duration, the need for it increases as the arrest duration increases. CPR was administered to some patients in the Minnesota study and in the casino study. The improved results in Boston were concomitant with not only an increase in available AEDs but with firefighter CPR training as well. Ewy, in discussing successes with a limited form of CPR which involves chest compression without ventilation, points out that rapid defibrillation and bystander initiated CPR are the major determinants of survival of a VF arrest (New England Journal of Medicine 2000; Vol. 342: Pgs. 1599-1560). A defibrillator device which could provide CPR instruction and guidance would be very advantageous. Although instruction prior to CPR could be automated, the processes of guidance during CPR and of suggesting corrective maneuvers during CPR, are far more easily accomplished by a human coach than by an algorithmic one.

[0042] Fifth, occasional malfunction of any electrical device is inevitable. Sweeny (cited above) noted seven instances of apparent AED malfunction out of 260 uses. It is far more likely that a medical professional who (i) has expert knowledge of a sophisticated defibrillator device and its backup systems, and (ii) constantly monitors the functioning of the defibrillator device during its operation, would be able to work around a device malfunction. (In the Sweeney study, use of AEDs in a Charlotte, N.C. EMS program did not result in outcome improvement.)

[0043] Sixth, in each of the reports cited herein, in which AEDs were used, their use was by a trained operator. It is inevitable that an untrained user will perform less accurately and take more time to do so. However, given that: (i) the ideal response time after an arrest would be even less than that during the casino study (in which victims were essentially under constant observation), and that (ii) the police or fire department response time is unlikely to ever be shorter than the casino response time; then the only likelihood of achieving the requisite ultra-short response time is by having a device that can be used by an entirely untrained bystander. Such a device would have to be more user-friendly than an AED. Such a device would have to be capable of both: (i) defibrillation, and (ii) closely linking an untrained bystander with an expert medical professional who could guide him through every aspect of the resuscitation process. AEDs do not meet this requirement. Indeed, the AEDs which have been installed to date typically display a warning to the potential user that the device is intended for use by trained personnel only.

[0044] Finally, since the aforementioned ideal external defibrillator device will require some level of participation by a human enabler (that is, a non-medically trained person who is available to use the device to defibrillate a victim of cardiac arrest), the creation of an environment in which the enabler functions optimally is critical. AEDs cannot address the anxiety or reluctance of an individual operator and may, in fact contribute to these. The cumulative effect of such feelings among a group of bystanders, may contribute to the chaos and pandemonium which not infrequently accompany a cardiac arrest. On the other hand, the voice of an experienced medical professional, taking charge, providing instructions, and making decisions, is often a great source of reassurance and stability, giving the assurance of proper conduct. AEDs cannot provide this human element.

[0045] Clearly, once a patient has suffered and survived an initial, life-threatening cardiac event, that patient must be monitored closely so that the proper treatment may be brought to bear on an emergency basis. The U.S. Pat. No. 5,544,661 to Davis et al. discloses a patient monitoring system which includes a portable device, attached to a patient, and a central station. The portable device includes an ECG and a photo-plethysmograph connected to the patient, and an arrhythmia analysis circuit which includes an expert system for determining whether pre-established critical parameters have been exceeded. The portable device also includes a wireless wide area communication circuit for automatically contacting the central station via a public cellular telephone network when the expert system determines that assistance is needed. When the central station is contacted, the patient's ECG waveforms, measurements and trends are sent to the central monitoring station and a two-way voice channel between the patient and the central station is automatically opened. The central station includes a computerized facility from which a clinician can observe both the real time data being sent from the patient and the patient's historical records. The clinician can talk to the patient through the two-way voice channel and can also activate therapeutic devices attached to the patient such as an external defibrillator, a pacer or an automatic drug infusion device.

[0046] Similarly, the U.S. Pat. No. 5,564,429 to Born et al. discloses a cardiorespiratory alert system which comprises a patient unit, a base station and a remote unit. In a hospital configuration, several patient units can communicate with the base station, which is located centrally, for example at a nurse's station. In a home configuration, the base station can reside near the patient's bedside. In both cases, the communication between the patient unit and the base station is by way of radio telemetry. The base stations are designed to communicate with a remote unit, either by radio telemetry or by use of commercial telephone lines.

[0047] The system provides alerts to the remote unit when life-threatening conditions are detected in a patient, yet it is tolerant to the presence of artifact so that false positive alerts are reduced.

[0048] Upon sensing a life-threatening condition, a “caregiver”, who staffs the remote unit or “dispatcher station”, may remotely activate various devices, including an external defibrillator, pacer and drug infusion device, and/or may contact an EMS unit in the patient's immediate locale, in an attempt to save the patient's life.

[0049] The subject matter of both the U.S. Pat. No. 5,544,661 and U.S. Pat. No. 5,564,429 is incorporated herein by reference.

[0050] The systems disclosed in these two patents require that the portable patient unit be worn at all times so that ECG and other patient critical information can be continuously monitored. These systems cannot be used in a normal emergency situation where a patient has no advance warning of a cardiac event and is therefore neither prepared nor monitored by a lifesaving system. The U.S. Pat. No. 5,184,620 discloses a method of monitoring a patient's cardiac activity using a so-called “electrode pad” having a plurality of electrode sites which, upon placement against the patient's chest wall, provide ECG signals for determining if cardiac pacing and/or defibrillation is required.

[0051] Certain combinations of electrodes provide the path for pacing signals whereas other combinations provide a path for defibrillation current.

[0052] The U.S. Pat. Nos. 5,593,426 and 5,782,878 (which have a similar disclosure) disclose a “communicator” for connecting each of a plurality of automatic external defibrillators (“AEDs”) to a central communication station. The central station receives information from an AED, such as patient ECG data and defibrillator operation data, and transmits information, such as use instructions for a bystander, to this AED.

[0053] The U.S. Pat. No. 4,102,332 describes a portable defibrillator, with a preprogrammed dialer, that telephones a physician when activated by a patient. While the physician and patient communicate with each other via the defibrillator's communication system, the physician can control the operation of the defibrillator from his or her remote location. During use, the defibrillator sends operation and status data to the physician.

[0054] The U.S. Pat. No. 6,141,584 discloses an automatic external defibrillator (AED) which is capable of storing ECG data and defibrillator data and “handing off” this data, via an infra-red link, to equipment of emergency medical personnel when they arrive on the scene of a cardiac arrest.

[0055] The U.S. Pat. No. 6,148,233 discloses a wearable automatic external defibrillator; that is, a defibrillator which is worn by a patient having one or more contact electrodes attached to the chest wall of the patient for transmitting defibrillation energy to the patient and for receiving ECG information from the patient. This patent is directed specifically to the contact electrode(s) which can be worn by a patient for a relatively long time without skin irritation or damage. This system is designed for patients who have previously experienced cardiac arrhythmias but are, perhaps, not ready for an implanted defibrillator/pacer.

[0056] Finally, there are numerous patents which relate to ICDs. Such devices, which are also a form of automatic defibrillator, are in constant electrical communication with the human heart. When implanted, such ICDs operate independently, without external controls, to treat ventricular fibrillation (VF), ventricular tachycardia (VT) and supraventricular arrhythmias by applying one or more voltage pulses to the heart.

[0057] In their formal definitions, cardioversion refers to the delivery of a shock which is synchronized to the heart's electrical activity and defibrillation refers to an asynchronous shock. For simplification, unless otherwise noted, either one of the terms cardioversion and defibrillation shall hereinafter be referred to as simply defibrillation, and either one of the terms cardiovertor and defibrillator shall hereinafter be referred to as simply defibrillator. Such simplification is not intended to narrow the scope of the invention described herein, but is merely for the purpose of avoiding repeated use of the respective lengthy and rather awkward medical terminology.

[0058] It is a principal object of the present invention to provide the services and superior ability of a highly-skilled medical professional (as compared to a fully automated apparatus) for diagnosing and treating cardiac arrest or any other cardiac rhythm abnormality. As used hereinafter, the term cardiac arrest is intended to include, and shall include, all types of cardiac rhythm abnormality.

[0059] It is a further object of the present invention to provide a system which can markedly decrease the response time of a medical professional to a cardiac arrest by facilitating lifesaving electrical therapy to the heart before the arrival of an emergency medical service or any other trained personnel.

[0060] It is a further object of the present invention to provide a system for resuscitation after the onset of cardiac arrest which affords: a) a degree of communication redundancy; b) a network of backup systems; and c) a certainty of execution of operator commands which are required for practical operation of the system by a remote medical professional.

[0061] It is a further object of the present invention to provide a system for resuscitation after the onset of cardiac arrest which can operate completely automatically in the event of a telecommunication breakdown or other fault which prevents a medical professional from using his or her judgment to control the operation of a defibrillator and/or pacing unit.

[0062] It is a further object of the present invention to allow a skilled medical professional to remotely monitor and manage a cardiac arrest which may occur at one of a plurality of remote sites, thus alleviating the anxiety and avoiding the pandemonium which often accompany the typical cardiac event. This skilled medical professional would be able to maintain a standard of care that an untrained or minimally trained AED user could not.

[0063] It is a further object of the present invention to provide a Universal Pad which may be used to apply multiple cardiac monitoring, pacing and defibrillation electrodes to the chest wall of a cardiac victim.

[0064] These objects, as well as further objects which will become apparent from the discussion that follows, are achieved, in accordance with the present invention, by providing a cardiac monitoring and external defibrillation system which comprises a central station and a plurality of remote, emergency site portable units, and a means for the central station to communicate with and control the remote site portable units. Once a remote site portable unit is attached to a victim of a cardiac arrest, the central station is capable of displaying selected items of real-time cardiac information for a human operator, in particular a medical professional, and issuing control signals, at the command of the medical professional, for controlling the application of defibrillation pulses to the victim. Prior to and after defibrillation pulses are applied, cardiac and possibly respiratory information is received from the cardiac victim at the remote site for evaluation by the medical professional. This information and information documenting all actions taken by the medical professional is automatically stored for subsequent download to an emergency medical team (EMT), a hospital, or other medical facility which eventually becomes responsible for care and treatment of the victim. Throughout the process of emergency care, the medical professional can communicate by voice and/or video and/or displayed text to instruct the emergency site enabler and to receive information from the enabler about the victim.

[0065] In particular, each of the plurality of remote sites is provided with an emergency cardiac monitoring and external defibrillation apparatus in the form of a portable unit. This apparatus includes a variety of means to apply contact electrodes to the chest wall of the cardiac victim. One such means is a Universal Pad; that is, a semi-rigid, flexible pad, adapted to be placed on the chest wall of a cardiac victim, which incorporates a plurality of cardiac contact electrodes at suitable positions for monitoring ECG signals and applying defibrillation and/or pacing pulses to the victim.

[0066] The portable unit at the remote site also includes a transmitting/receiving device for sending cardiac and respiratory information to, and receiving control signals from, the central station and for sending and receiving voice, text and video.

[0067] The remote site portable unit also includes a defibrillator circuit, connected to the contact electrodes for applying high voltage defibrillation pulses to these electrodes in response to defibrillation control signals received from the central station. The remote site apparatus may include a cardiac pacing circuit, connected to the contact electrodes for applying lower voltage cardiac pacing pulses to these electrodes in response to pacing control signals received from the central station.

[0068] The cardiac monitoring and external defibrillator system, according to the invention, provides and incorporates a number of advantageous features. These include:

[0069] Enabling the medical professional at the central station to decide whether the situation merits use of the emergency apparatus at the remote site;

[0070] Enabling the medical professional to summon the local emergency medical service (i.e. by contacting the “911” emergency service in the locale of the remote site);

[0071] Enabling the medical professional to direct the initial application of the Universal Pad and/or other contact electrodes on the victim's body;

[0072] Enabling the medical professional to direct a subsequent application of the Universal Pad and/or other contact electrodes when the initial therapy did not succeed for any reason; for example, due to incorrect placement of the electrodes or due to anatomic or other considerations.

[0073] Enabling the medical professional to compensate for less than perfect orientation of the electrodes applied to the victim's chest wall without reapplying the Universal Pad;

[0074] Enabling the medical professional to view the victim's ECG and make a rhythm diagnosis whose accuracy can exceed the best algorithm of fully automated defibrillation equipment;

[0075] Enabling the medical professional to make a determination as to whether any one or more of the contact electrodes are making poor contact with the victim's chest wall, and to compensate for such poor contact;

[0076] Enabling the medical professional to defibrillate along different spatial axes, and/or different points on the victim's body, thereby increasing the chance of a successful outcome during a cardiac arrest;

[0077] Enabling the medical professional to deliver alternate therapies including pacing;

[0078] Enabling the medical professional to decide whether high energy shock, low energy shock, pacing and/or CPR, or perhaps no therapy at all, is appropriate;

[0079] Enabling the medical professional to control multiple parameters of electrical therapy including voltage, pulse width, pulse shape, pulse energy and timing;

[0080] Enabling the medical professional to instruct the enabler in the proper CPR technique;

[0081] Enabling the medical professional to monitor and, if necessary, correct the enabler in the proper performance of cardiopulmonary resuscitation (CPR);

[0082] Enabling the medical professional to assess the victim's respiratory and blood pressure status;

[0083] Enabling a single medical professional to supervise a plurality of enablers at different cardiac arrest scenes;

[0084] Enabling a medical professional to triage the supervision of simultaneously occurring cardiac arrests to other medical professionals;

[0085] Enabling the medical professional to avoid chaos, panic, inaction, delayed action or inappropriate action by allowing this medical professional to supervise emergency scene enablers;

[0086] Enabling the medical professional to release a lock holding the portable unit to a wall or to another stationary object, or to a wall-mounted stationary unit at the remote site of the cardiac arrest;

[0087] Enabling the medical professional to see a victim of cardiac arrest, an enabler at the scene, the placement of cardiac electrodes on the victim's chest as well as the administration of CPR;

[0088] Enabling the medical professional at the central station, and/or the system itself, to diagnose a failing component or group of components of the system and to bypass or provide a substitute for these components;

[0089] Enabling the medical professional at the central station, or the system itself, to assess the existence and/or maintenance of proper communication between the central station and the remote site of the cardiac arrest and to remediate any problem by switching a communication channel, route or modality in any segment of the communication links;

[0090] Enabling the medical professional to utilize communication modalities other than voice, such as text and/or video; Enabling the medical professional to receive a confirmation signal that a command, such as a command to defibrillate with a specific shock energy and with specific cardiac electrodes, was duly executed;

[0091] Enabling the medical professional to receive error signals indicating that a command was not properly executed or that either the remote equipment or the central station has malfunctioned;

[0092] Enabling the medical professional, and/or the system itself, to switch to an AED backup if necessary;

[0093] Enabling the medical professional, and/or the system itself, to transfer control of the portable unit to an emergency medical team, if necessary and if appropriate;

[0094] Enabling the medical professional to properly identify emergency medical personnel, before transferring control of the portable unit to such personnel;

[0095] Enabling the medical professional to properly brief emergency medical personnel on events which transpired before their arrival at the scene of the emergency;

[0096] Enabling the medical professional to assist emergency medical personnel during and after a cardiac arrest by accessing databases which may contain information about the victim and/or his medications and/or his implanted pacemaker or defibrillator (if any);

[0097] Enabling the medical professional to assist emergency medical personnel during and after a cardiac arrest by monitoring the victim's cardiac and respiratory status;

[0098] Enabling the medical professional to assist emergency medical personnel during and after a cardiac arrest by providing advice and guidance concerning the medical management of the victim;

[0099] Enabling the medical professional to assist emergency medical personnel during and after a cardiac arrest by providing advice and guidance concerning the operation of the portable unit;

[0100] Enabling the medical professional or other trained personnel to supervise the reattachment of the portable unit to the wall or to the stationary unit or its return to the position in which it was located prior to the cardiac arrest;

[0101] Enabling the medical professional or other trained personnel to supervise the restocking of the portable unit;

[0102] Enabling the medical professional or other trained personnel to visually inspect the portable and stationary units;

[0103] Enabling the medical professional or other trained personnel to assess the electrical and mechanical functioning of the portable and stationary units;

[0104] Enabling the medical professional to maintain a complete, secure, encrypted record of the events and data related to a cardiac arrest;

[0105] Enabling the medical professional to transmit information concerning the arrest in a secure, encrypted manner, in accordance with local and federal statutes and regulations;

[0106] Enabling the medical professional to control the function of an implanted medical device;

[0107] Enabling the medical professional to work with a foreign language speaking enabler via an interpreter, or a computer program which performs such function; and

[0108] Enabling the medical professional to deal with a potential prankster or vandal by visually identifying such individual.

[0109] According to a particular feature of the invention, the emergency cardiac monitoring and external defibrillation apparatus, which is disposed at each of a plurality of remote sites, is divided into two separate units:

[0110] (1) a stationary unit, adapted for permanent installation at the remote site, which is capable of communicating with the central station and has a transmitting/receiving device for electronic communication with a portable unit; and

[0111] (2) a portable unit, releasably attached to the stationary unit, which has a transmitting/receiving device for electronic communication with the stationary unit.

[0112] The portable unit and the stationary unit are joined together by a releasable lock which is controlled from the central station by a portable unit release signal. When the medical professional determines that an enabler should take the portable unit to the side of a cardiac victim, he may generate and transmit the portable unit release signal.

[0113] Advantageously, the portable unit is provided with a sensor for sensing when it has been released from attachment to the stationary unit. The portable unit is preferably also provided with a sensor to sense when the portable unit has been placed on the floor next to a victim with a proper orientation of the unit (i.e., with the proper side up).

[0114] According to a particular feature of the present invention, the stationary unit comprises a battery charger and the portable unit comprises a battery for powering the electronic circuits therein. When the portable unit is attached to the stationary unit, the battery charger maintains the battery in a charged condition. The stationary unit may also be provided with a battery backup to safeguard against a power failure.

[0115] To initiate the operation and to alert the medical professional, the portable unit is preferably provided with a button, to be pressed by someone (e.g., a bystander) in the vicinity of the victim, in the case of a medical emergency. This button may, for example, have a large red cross and/or the words “MEDICAL EMERGENCY” imprinted thereon. The person who presses this button, and then becomes an “enabler”, facilitates or “enables” the resuscitation of the victim under the direction of the medical professional. Pressing the button initiates the communication process between the enabler and the medical professional.

[0116] Although the preferred communication modality is from portable unit to and from stationary unit by radio frequency, and from central station to and from the stationary unit via public access telephone company land line, the medical professional or the system can, if desirable, select an alternate route. Examples of such selections would include using a radio frequency link between the central station and the stationary unit, or bypassing the stationary unit, with a link from the portable unit to the central station. Furthermore, although the public telephone network may be used, a private network or the Internet could also be used.

[0117] In a preferred embodiment the system initially establishes proper function of the communication components, which link the central station and the portable unit during the first step or layer of a handshake routine. A series of such handshakes occurs, each incorporating the previous one and each encompassing a larger circle of sub-systems, until there is complete informational exchange between the medical professional and the enabler. Such handshakes are utilized throughout the duration of the cardiac arrest to ensure robust and reliable communication between the medical professional and each of the enabler, the victim (in which case the communication consists of an electrical link) and the emergency medical team. Each handshake is rendered least likely to fail by the availability of multiple levels of backup systems

[0118] Once the basic communication handshake has been effected, the proper functioning of the next layer of components is quickly confirmed. This layer includes the ability of the system to send and receive voice and data in each direction, the ability of the medical professional to properly transmit commands, and the proper receipt of the commands by the portable unit. Diagnostic features within the system allow for the identification of and substitution for a failing sub-system or sub-unit within either the central station, the stationary unit or the portable unit. Such identification and substitution may be performed with or without the active participation of the medical professional.

[0119] Thereafter, according to a particular feature of the present invention, the handshaking is extended to include actual communication between the medical professional and the enabler. In particular, the medical professional will attempt to verbally communicate with the enabler in the local language.

[0120] According to a preferred feature of the invention, at least voice communication is made available between the portable unit and the central station. Advantageously, the words spoken by the medical professional are displayed as text on the portable unit so that the enabler may see as well as hear the instructions given. A video link is also desirable and, in accordance with a preferred feature of the invention, the medical professional at the central station is provided with a device for remotely controlling the orientation of a video camera on the portable unit, so that the medical professional may best see the enabler, the victim and even the portable unit itself. To facilitate hands-free voice communication with the enabler at the remote site, the portable unit is preferably provided with a microphone and loudspeaker, and with a headset which contains earphone and microphone.

[0121] In the event that proper communication between the medical professional and the enabler can not be established and/or maintained, backup AED function is available. The portable unit will select the AED function if either the initial handshake fails, or if there are either substantial interruptions to, or degradation of a previously established communications link. AED control can also be selected by the medical professional if he deems the quality of the communications link to be inadequate.

[0122] The medical professional may continue to monitor an event even though control may have been handed over to the AED. If the medical professional later finds that robust communication has been re-established, he may resume and take control back from the AED. In such a case, the medical professional would be able to securely download the encrypted information pertaining to any gap in the data/event sequence, from the data storage unit within the portable unit.

[0123] A master control unit within the portable unit selects which person, or which circuitry controls the executive functioning of the portable unit. When communication with the central station is established, the master control unit lets the medical professional control executive functioning. A communications failure results in the AED having control. When one or more members of an emergency medical team is/are present, the master control unit is designed to give this team the opportunity to control the portable unit. Yet another function of the master control unit is to allow a remote person to perform diagnostic testing and information exchange with the portable unit.

[0124] Following the initial establishment of communication between the medical professional and the enabler, the medical professional may ask the enabler for a description of the event and may thereby decide whether release of the portable unit from the stationary unit is appropriate. Thereafter, if and when the portable unit is released, the enabler may be directed to carry the unit to the victim's side.

[0125] At this point the medical professional may instruct the enabler as to the proper selection, positioning and application of the contact electrodes and/or the Universal Pad.

[0126] Once the electrodes have been applied, the medical professional will begin to receive and review ECG data from the victim. Based on this information the medical professional will use his judgment to decide upon the proper initial therapy. For example, the medical professional may decide to apply a defibrillation pulse of a particular energy and waveform through a particular combination of electrodes. Alternatively, the medical professional may decide that pacing is a more appropriate therapy or that no electrical therapy is needed.

[0127] After the administration of the initial electrical therapy the medical professional will reassess the condition of the victim, by using the transmitted ECG and other transmitted data, and decide upon the next step.

[0128] In particular, if the first therapy was either unsuccessful, partially successful or transiently successful, the medical professional may elect to either repeat the identical therapy or to modify it, either qualitatively or quantitatively. For example, if a 100 joule shock applied between one particular pair of electrodes (e.g., specific ones of the electrodes on the Universal Pad) was unsuccessful, the medical professional might then elect to apply a 150 joule shock between a different combination of two or more electrodes on the Universal Pad.

[0129] In order for a medical professional to properly and safely administer remote therapy during an emergency situation, he needs to receive reliable confirmation that each command: a) was properly sent from the central station; b) was properly received at the remote site; and c) was properly executed. With a confirmation system in place, if a command for a particular therapy is not followed by the restoration of a normal rhythm, the medical professional can conclude that the therapy itself failed; rather than having to consider the possibility that treatment failure may have resulted from a failure of the system to actually render the medical professional-directed treatment.

[0130] Cardiopulmonary resuscitation (CPR) can substantially improve the outcome of certain cardiac arrests, especially if electrical therapy does not rapidly restore normal cardiopulmonary function. If and when the medical professional feels that CPR is a desirable adjunct to electrical therapy, he may instruct or coach the enabler in proper CPR technique. The instruction may be via video and/or audio transmission from the central station to the portable unit during the arrest.

[0131] At the time that the portable unit is released, the cardiac monitoring system according to the invention may automatically contact the local emergency unit. When such emergency personnel arrive, the medical professional can hand off some or all responsibility to the on-scene emergency medical team (EMT), after the EMT has been properly identified.

[0132] For this to occur, the medical professional would issue a command to the master control circuit. This would convert the portable unit into a manually controlled device. The medical professional could then continue to observe and advise in such a situation.

[0133] In addition to monitoring ECG signals from the victim, the portable unit may be provided with a blood pressure measuring device (e.g., an automatic cuff for measuring systolic and diastolic pressure of the victim); and/or a pulse oximetry monitoring device for measuring the blood oxygen content of the victim.

[0134] As used herein, the term “pulse oximetry” is intended to include the measurement of any blood gases (oxygen, carbon dioxide and the like), blood pH, blood sugar or any other blood component.

[0135] According to a further aspect of the invention, the Universal Pad is a multi-electrode pad which includes five defibrillator electrodes arranged in two separate rows with two electrodes in a first, upper row and three electrodes in a separate, lower row. These electrodes may be used in combinations of two or more for defibrillation, pacing and/or ECG recording. Advantageously, a plurality of ECG electrodes, which are smaller than the defibrillator electrodes, are distributed adjacent to the five defibrillator electrodes; These electrodes may be used in combinations of two or more for ECG recording. Alternatively, ECG recording may be accomplished using a mixture of defibrillator electrodes and ECG electrodes.

[0136] In another embodiment of the Universal Pad, the electrodes are arranged in a matrix of many separated electrodes. This gives the medical professional additional flexibility in selecting combinations of two or more electrodes to which defibrillation and/or pacing pulses are to be applied and from which ECG signals are to be received.

[0137] Other arrangements of contact electrodes, adapted for application to the victim's body, may also be used. For example, the portable unit may be operated with two or more standard individual contact electrodes for receiving ECG signals and applying defibrillation and/or pacing pulses.

[0138] According to a particular feature of the present invention, the Universal Pad, or any of the contact pads, may be provided with a protective and insulating backing that is peeled off prior to use. Means are provided to signal to the medical professional at the central station when the backing is peeled off. When the backing is peeled off, the medical professional is informed as to which electrode pad, from among a variety of pads with different electrode configurations, is actually being used by the enabler.

[0139] According to a particular feature of the invention, the male and female versions of the cable connectors which link the electrode pads with the portable unit, hereinafter referred to as Universal Connectors, allow a number of advantageous features. These include: a) the ability to attach any of a variety of electrode pads which terminate in a female Universal Connector, to any male Universal Connector of the portable unit; b) the ability of the medical professional to know which (if any) particular variety of pad is attached to each of the portable unit Universal Connectors; and c) the ability of the medical professional to know when the backing material has been removed from an electrode pad.

[0140] According to a particular feature of the invention, a video system is provided which serves the following functions:

[0141] a) If one way video is provided from the portable unit to the central station:

• • [0142] (i) It lets the medical professional view an incorrect pad orientation and advise the enabler to correct it.
  • [0143] (ii) It lets the medical professional directly visualize the victim for diagnostic and management purposes: state of consciousness, presence of seizure activity, head positioning.
  • [0144] (iii) It allows the medical professional to give advice concerning CPR technique.
  • [0145] (iv) It is useful for ruling out a prankster, in the event that initial button press is followed by absent, inadequate or inappropriate verbal response from a potential enabler.
  • [0146] (v) During a system diagnostic check, the video camera may be oriented to inspect the physical integrity of the portable and stationary units.
  • [0147] b) If two way video is provided between the portable unit and the central station:
  • [0148] (i) It allows the medical professional to illustrate proper defibrillator pad positioning and orientation. The correct position and orientation could be shown as a cartoon or virtual image superimposed on the actual image of the victim.
  • [0149] (ii) It allows detailed illustration of CPR technique. This too could be superimposed or overlaid onto the actual image of the victim.
  • [0150] (iii) It can help the medical professional to identify various components of the system to the enabler by displaying them.
  • [0151] (iv) It can help the medical professional to instruct the enabler as to the application of blood pressure measuring, pulse oximetry and ancillary paraphernalia included in the tool-kit of the portable unit.
  • [0152] (v) An image of the medical professional may have a reassuring effect upon the enabler and upon other bystanders.

[0153] In another preferred embodiment of the present invention, the medical professional may guide a person who is returning the previously used portable unit to the location in which it is intended to remain when not in use. Such guidance may include: a) information about replacing and restocking components of the portable unit tool-kit; b) information about the location to which the portable unit must be returned; and c) positioning and orienting information to allow the portable unit to be properly attached to a stationary unit or stationary lock.

[0154] In another preferred embodiment of the invention a global positioning system within the portable unit may allow the medical professional to know the location of any such portable unit. This would facilitate the medical professional's ability to keep track of the location of each portable unit, especially if it has been transported to a substantially different location during or after its use. It would also let the medical professional ascertain the location of an en-route EMT, if the EMT was transporting a portable unit which was equipped with a global positioning system.

[0155] In another preferred embodiment of the present invention, the central station and/or the emergency defibrillation apparatus disposed at the remote sites include a storage device which stores the ECG signals and possibly other data received from the victim and the control and other signals transmitted from the central station. In addition, the voice, text and video communications may be stored for later review. In this way, a cardiac arrest “event” can be analyzed and reviewed for later instructional, medical and legal purposes. Such storage, review and analysis would be in compliance with pertinent local and federal statutes and regulations.

[0156] A still further advantageous feature of the present invention includes providing means at the portable unit (such as a keyboard, real or virtual) to permit communication with the central station by text, in the event of breakdown in voice communication. As already mentioned above, the instructions of the medical professional at the central station, which are normally transmitted by voice, can be displayed in text at the portable unit. Another alternative communications interface with the enabler would include portable unit or central station initiated voice prompts and/or speech recognition.

[0157] According to a particular, advantageous feature of the present invention, means are provided at the portable unit to transmit control signals to and receive data signals from an ICD or a pacemaker, which has been previously implanted in the victim's chest. In this way, a medical professional may attend to the emergency medical needs of this type of victim as well. In this case, the contact electrodes which receive ECG signals and which transmit defibrillator and/or pacing pulses to the heart have already been implanted, thus eliminating the need for an enabler to place any contact electrodes on the victim's chest.

[0158] According to a particular feature of the invention, communication between the portable unit and the central station may traverse a route in which there may be more than one stationary unit and/or one or more additional portable units, with each of said stationary units and said additional portable units functioning as a repeater, i.e. as a communications relay.

[0159] Finally, it is contemplated that in a large, extensive system with many portable units at various remote sites more than one cardiac arrest may occur simultaneously. Accordingly, the invention provides means for: a) a single medical professional supervising multiple simultaneous arrests; b) one central station with multiple attendant medical professionals and a means for triaging the supervision of cardiac arrests among them; and c) a network of central stations, each with one or more attendant medical professionals, and a means for triaging the supervision of cardiac arrests among them.

[0160] For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawings.

1. System Overview

[0236] 1.1 Description of the Emergency Scene

[0237] 1.2 Description of the Central Station

[0238] 1.3 Block Diagram of the System

• • [0239] 1.3.1 Two Unit System: Portable Unit and Central Station
  • [0240] 1.3.1.1 System Operation when PU-CS Link is Intact
  • [0241] 1.3.1.2 AED Backup in the Event of Communication Failure; Role of the Master Control Unit
  • [0242] 1.3.2 Three Unit System: Portable Unit, Stationary Unit and Central Station

[0243] 1.4 Figure Assignments

2. Portable Unit and Stationary Unit: Exterior Elements

[0244] 2.1 Portable Unit: Front and Right Side Panels

[0245] 2.2 Portable Unit: Tool-kit

[0246] 2.3 Portable Unit: Rear and Left Side Panel

[0247] 2.4 Stationary Unit: Front and Side Panels

[0248] 2.5 Portable Unit: Screens

3. Electrode Pads

[0249] 3.1 Physiology of Defibrillation

[0250] 3.2 Torso-Shaped Multi-electrode Pads

[0251] 3.3 Matrix Electrode Pad

[0252] 3.4 Single Electrode Pads

4. Sample Cardiac Arrest and System Operation

[0253] 4.1 Overview of Sample Arrest

• • [0254] 4.1.1 Phase One: Initial Enabler Action
  • [0255] 4.1.2 Phase Two: Handshakes Linking Enabler and MP
  • [0256] 4.1.2.1 Role Played By Handshakes; Relationship Between Handshakes and Backups; Relationship Between Handshakes and Links
  • [0257] 4.1.2.2 Backup Systems for a Failed Handshake
  • [0258] 4.1.2.3 Four Handshakes which Link the Enabler and the MP
  • [0259] 4.1.2.3.1 The Communication Handshake
  • [0260] 4.1.2.3.2 The Data/Commands Handshake
  • [0261] 4.1.2.3.3 The Audio Handshake
  • [0262] 4.1.2.3.4 The Informational Handshake
  • [0263] 4.1.2.4 Role of the Stationary Unit in the Handshake Protocol
  • [0264] 4.1.2.4.1 Single Direct Link Between PU and CS as the Default Routing Approach; Stationary Unit Functions as a Backup
  • [0265] 4.1.2.4.1.1 Direct PU-CS Link Can Not Be Established; Failure of One But Not Both Possible PU-SU Connections; Successful SU-CS Connection
  • [0266] 4.1.2.4.1.2 Direct PU-CS Link Can Not Be Established; Failure of Both Possible PU-SU Connections and/or Failure of SU-CS Connection
  • [0267] 4.1.2.4.2 Two Connections: One from PU to SU and One from SU to CS as the Default Routing Approach
  • [0268] 4.1.2.4.2.1 Two-Segment Default; Initial PU-CS Link Successful
  • [0269] 4.1.2.4.2.2 Two-Segment Default; Initial PU-CS Link Unsuccessful
  • [0270] 4.1.2.4.3 Redundant Links, in which There is Both a Direct PU-CS Link and an Indirect PU-SU-CS Link
  • [0271] 4.1.2.4.4 More Elaborate Routes for the PU-CS Link
  • [0272] 4.1.2.4.5 Depth of Handshake Layers
  • [0273] 4.1.3 Phase Three: Transport of PU to Victim; Victim—MP Handshake; PU Setup at Victim's Side
  • [0274] 4.1.3.1 PU Release and Transport
  • [0275] 4.1.3.2 Handshakes Linking Victim and MP
  • [0276] 4.1.3.2.1 The Four Layer Victim—MP Link
  • [0277] 4.1.3.2.2 Backup Systems for Failure in the Victim—MP Link
  • [0278] 4.1.3.3 MP Commands, Confirmation Signals and Error Signals
  • [0279] 4.1.3.4 Telemetry Signals
  • [0280] 4.1.4 Emergency Medical Management of the Cardiac Arrest by the Medical Professional
  • [0281] 4.1.4.1 Defibrillation and Pacing by the MP
  • [0282] 4.1.4.2 Other Actions Directed by the MP to Support Blood Pressure
  • [0283] 4.1.5 Phase Five: Management Immediately Post Electrical Resuscitation
  • [0284] 4.1.6 Phase Six: EMT Arrival, Transfer of Control of the PU from MP to EMT
  • [0285] 4.1.6.1 EMT Choices Other Than Assuming Control of the PU Currently Attached to the Victim
  • [0286] 4.1.6.2 Handshakes Linking EMT and MP
  • [0287] 4.1.6.2.1 First and Second Layers of EMT-MP HS:

[0288] Password which Gives Control of PU to EMT, Rather Than Giving Control of PU to AED/P

• • [0289] 4.1.6.2.2 Third and Fourth Layers of EMT-MP HS
  • [0290] 4.1.7 Management by the EMT, after Transfer of PU Control to the EMT, by the MP
  • [0291] 4.1.7.1 Transfer of PU Control
  • [0292] 4.1.7.2 Briefing of EMT by MP
  • [0293] 4.1.7.3 Method of PU Operation by the EMT
  • [0294] 4.1.7.4 MP Role During EMT Use of the PU
  • [0295] 4.1.7.4.1 Medical and Technical Support by the MP
  • [0296] 4.1.7.4.2 Pharmacologic Support by the MP
  • [0297] 4.1.8 MP Role After Victim Arrives at the Hospital

[0298] 4.2 Sample Cardiac Arrest: Correspondence Between Events During the Arrest, Flow Diagrams, Screens, Handshakes and Confirmation Signals

[0299] 4.3 Role of the Medical Professional

• • [0300] 4.3.1 Expert Decisions Made by the MP During the Cardiac Arrest
  • [0301] 4.3.1.1 MP Decision to Change the Defibrillation Vector for the Second Shock
  • [0302] 4.3.1.2 MP Distinction Between Asystole and Ventricular Fibrillation
  • [0303] 4.3.1.3 MP Action to Improve Victim's Blood Pressure
  • [0304] 4.3.1.4 Other MP Decisions Requiring Medical Expertise
  • [0305] 4.3.2 Enabler Guidance by the MP
  • [0306] 4.3.2.1 Enabler Guidance in Proper Application of the Electrode Pad
  • [0307] 4.3.2.2 Enabler Guidance in Cardiopulmonary Resuscitation
  • [0308] 4.3.2.3 Enabler Guidance in Other Activities
  • [0309] 4.3.3 EMT and Physician Guidance by the MP

[0310] 4.4 Time Allocation During the Sample Cardiac Arrest

• • [0311] 4.4.1 General Considerations Regarding Prediction of Duration
  • [0312] 4.4.2 Enabler Travel Time
  • [0313] 4.4.3 Duration of Other Enabler Tasks
  • [0314] 4.4.4 Time Allocation for MP Tasks During Phase Four
  • [0315] 4.4.5 Time Allocation Involving EMT Events
  • [0316] 4.4.6 Correction for Simultaneous or Nearly Simultaneous Tasks or Events

[0317] 4.5 Further Details Concerning Specific Issues During the Sample Cardiac Arrest

• • [0318] 4.5.1 Phase One: Amount of Time for Enabler to Reach PU
  • [0319] 4.5.2 Specific Issues During Phase Two
  • [0320] 4.5.2.1 Initial and Subsequent MP Screens
  • [0321] 4.5.2.2 Facilitated Lock Release in the Event of Failure of Handshake #1 or #2
  • [0322] 4.5.3 Specific Issues During Phase Three
  • [0323] 4.5.3.1 The MP Interface with Emergency Medical Services
  • [0324] 4.5.3.2 Enabler Action During Transport of PU to Victim
  • [0325] 4.5.3.3 MP Assessments and Actions, Upon Arrival of the PU at the Victim's Side
  • [0326] 4.5.3.4 Enabler Headset Handshake
  • [0327] 4.5.4 Specific Issues During Phase Four
  • [0328] 4.5.4.1 Wide Variety of MP Choices for Defibrillation and Pacing Parameters; Central Station Screens which Correspond to these Choices
  • [0329] 4.5.4.2 MP Instructs Enabler in the Application of Blood Pressure and Blood Oxygen Saturation Devices
  • [0330] 4.5.5 Specific Issues During Phase Five
  • [0331] 4.5.5.1 Possible Performance of CPR During Phase Five
  • [0332] 4.5.5.2 Multiple Possible Types and Sources of Victim Related Information
  • [0333] 4.5.5.3 Multiple Possible Means of Tracking Local Emergency Services
  • [0334] 4.5.6 Specific Issues During Phase Six
  • [0335] 4.5.6.1 Analogous Aspects of the Enabler-MP Link During Phase Two, and the EMT-MP Link During Phase Six
  • [0336] 4.5.6.2 Timing of EMT Arrival
  • [0337] 4.5.6.2.1 Time Saved by Using the Invention: Estimation of the Earliest Possible Defibrillation by EMT, Without the Invention
  • [0338] 4.5.6.2.2 More Realistic Estimates for EMT Defibrillation
  • [0339] 4.5.7 Specific Issues During Phase Seven
  • [0340] 4.5.7.1 Overview of Phase Seven: Two Sequences of Events
  • [0341] 4.5.7.1.1 Analogous Aspects of Phase Seven and Phase Three
  • [0342] 4.5.7.1.2 Two vs. One Portable Unit at the Arrest Scene
  • [0343] 4.5.7.2 Two Portable Units Available: New Versus Old PU as the Replacement Unit
  • [0344] 4.5.7.2.1 Option One: Old PU Remains Attached to the Victim; New PU to be Attached to the Stationary Unit; Transportation of the New PU to the SU
  • [0345] 4.5.7.2.2 Option Two: New PU is Attached to the Victim; Old PU to be Reattached to the Stationary Unit
  • [0346] 4.5.7.3 Housekeeping Activities Before Returning the Old PU to the SU; Transportation of the Old PU to the SU
  • [0347] 4.5.7.3.1 MP Role During Housekeeping
  • [0348] 4.5.7.3.2 Choice of Individual to Perform the Housekeeping Activities
  • [0349] 4.5.7.3.3 Electrode Pad Replacement; Oximetry Sensor Replacement
  • [0350] 4.5.7.3.4 Replacement of Non-Disposable Items
  • [0351] 4.5.7.3.5 Video Boom and Antenna Retraction Prior to Moving the PU
  • [0352] 4.5.7.3.6 Transportation of the Old PU to the SU
  • [0353] 4.5.7.4 Attachment of the PU to the SU
  • [0354] 4.5.7.4.1 Who Performs the Attachment?
  • [0355] 4.5.7.4.2 Mechanical Issues in the Attachment Process
  • [0356] 4.5.7.4.3 Endpoint for PU-SU Attachment
  • [0357] 4.5.7.4.4 Checking the PU Post-Attachment
  • [0358] 4.5.7.5 Choices in the Event of Communications Failure During Phase Seven
  • [0359] 4.5.7.5.1 EMT Communications Choices Using Only One Portable Unit
  • [0360] 4.5.7.5.2 EMT Communications Choices Using a Second Portable Unit
  • [0361] 4.5.7.5.2.1 Choice in which PU-2 is the Only PU which Communicates with the Central Station
  • [0362] 4.5.7.5.2.2 Choices in which Both PU-1 and PU-2 are Used in Tandem; Even More Elaborate Links
  • [0363] 4.5.7.6. Possible Need for Two Nearly Simultaneous MP Conversations During Phase Seven
  • [0364] 4.5.7.7 The Circumstance in which EMT Does Not Bring a Replacement PU
  • [0365] 4.5.7.7.1 Option Three: Sole PU Remains at the Arrest Scene
  • [0366] 4.5.7.7.2 Option Four: Sole PU is to be Transported with the Victim
  • [0367] 4.5.7.8 Protocol Endpoints During Phase Seven
  • [0368] 4.5.7.8.1 Definition of Victim Detachment from PU
  • [0369] 4.5.7.8.2 Circumstances in which a PU Would Not Be Promptly Replaced
  • [0370] 4.5.7.8.2.1 PU Non-Replacement at the Arrest Site
  • [0371] 4.5.7.8.2.2 Non-Replacement of the EMT PU

[0372] 4.6 Post-Arrest Issues

• • [0373] 4.6.1 On-Site Equipment Inspection and Assessment
  • [0374] 4.6.1.1 Timing of the On-Site Visit
  • [0375] 4.6.1.2 Items Assessed During the On-Site Evaluation Process
  • [0376] 4.6.2 Remote Equipment Inspection and Assessment
  • [0377] 4.6.2.1 Timing of the Remote Evaluation Process
  • [0378] 4.6.2.2 Items Assessed During the Remote Evaluation Process
  • [0379] 4.6.3 PU and SU Hardware and Software Updates
    5. Flow Diagrams

[0380] 5.1 Communications Handshake

• • [0381] 5.1.1 Overview
  • [0382] 5.1.2 Communications Handshake, PU Component
  • [0383] 5.1.3 Communications Handshake, CS Component
  • [0384] 5.1.4 Handshakes During Diagnostic Checking

[0385] 5.2 The Data/Commands Handshake

[0386] 5.3 Audio and Informational Handshakes

• • [0387] 5.3.1 Part I, Audio Handshake
  • [0388] 5.3.2 Audio Handshake, Part II
  • [0389] 5.3.2.1 Using Voice Prompts
  • [0390] 5.3.2.2 Without Voice Prompts, Version 1
  • [0391] 5.3.2.3 Without Voice Prompts, Version 2
  • [0392] 5.3.3 Audio Handshake, Part III
  • [0393] 5.3.4 Informational Handshake

[0394] 5.4 PU Transport and Setup at the Victim's Side

• • [0395] 5.4.1 PU Transport
  • [0396] 5.4.2 PU Arrival at Victim; PU Setup
  • [0397] 5.4.2.1 PU Touchdown and Video Setup
  • [0398] 5.4.2.2 Audio Communications Adjustment, If Necessary
  • [0399] 5.4.2.2.1 Audio Communications Overview
  • [0400] 5.4.2.2.2 Audio Communications Flow Diagram Following PU Touchdown
  • [0401] 5.4.2.3 Non-Audio Communication Backups
  • [0402] 5.4.2.4 Initial Victim Assessment
  • [0403] 5.4.2.5 Electrode Pad Application
  • [0404] 5.4.2.6 Electrode Pad Assessment

[0405] 5.5 Flow Diagrams: Arrhythmia Management

• • [0406] 5.5.1 First Tier Arrhythmia Triage Protocol
  • [0407] 5.5.1.1 Overview
  • [0408] 5.5.1.2 Details of Arrhythmia Triage
  • [0409] 5.5.1.2.1 Bradycardia/Paced Rhythm Decision
  • [0410] 5.5.1.2.2 Tachycardia/No Tachycardia Decision
  • [0411] 5.5.1.2.3 Options in the Event that the Rhythm Diagnosis is Uncertain
  • [0412] 5.5.1.3 Other Approaches to First Tier Arrhythmia Triage
  • [0413] 5.5.2 Shock Administration Protocol
  • [0414] 5.5.3 Second Tier Arrhythmia Triage Protocol
  • [0415] 5.5.3.1 Overview
  • [0416] 5.5.3.2 Alternative Tachycardia Termination Techniques
  • [0417] 5.5.3.3 The MP's Assessment of the Appropriateness of the Use of Alternative Tachycardia Termination Techniques
  • [0418] 5.5.3.4 Algorithm for Considering Alternative Tachycardia Termination Techniques Based on State of Consciousness, Respiratory Status and Blood Pressure
  • [0419] 5.5.4 Anti-Tachycardia Pacing
  • [0420] 5.5.4.1 Background
  • [0421] 5.5.4.2 Anti-Tachycardia Pacing Protocol
  • [0422] 5.5.4.3 Other Possible Anti-Tachycardia Pacing Protocols
  • [0423] 5.5.5 Bradycardia/Pacing Protocol
  • [0424] 5.5.5.1 Overview
  • [0425] 5.5.5.2 External Pacing Not in Progress; MP Decision Whether to Start Pacing
  • [0426] 5.5.5.3 External Pacing Is in Progress; MP Decision Whether to Check Underlying Rhythm
  • [0427] 5.5.5.4 MP Considerations Concerning Termination of Pacing

[0428] 5.6 Command Confirmation

6. Central Station Screens

[0429] 6.1 Basic Communications Screens

• • [0430] 6.1.1 Communication Status and Master Control Screen
  • [0431] 6.1.2 Voice Prompt Screen

[0432] 6.2 Portable Unit Setup Screens

• • [0433] 6.2.1 Portable Unit Deployment Screen
  • [0434] 6.2.2 The Video Control and Instruction Screen
  • [0435] 6.2.3 Initial ECG Screen

[0436] 6.3 Arrhythmia Management Screens

• • [0437] 6.3.1 Defibrillation Management Screens
  • [0438] 6.3.1.1 Paths to Main Defibrillation Screen
  • [0439] 6.3.1.2 Method of Operation: Defibrillation Screens
  • [0440] 6.3.1.2.1 Default Values: Main Defibrillation Screen
  • [0441] 6.3.1.2.2 Non-default Values
  • [0442] 6.3.1.2.2.1 Defibrillation Energy Screen
  • [0443] 6.3.1.2.2.2 Synchronization Screen
  • [0444] 6.3.1.2.2.3 Pulse Shape Screen
  • [0445] 6.3.1.2.2.4 Electrode Setup Screens
  • [0446] 6.3.1.2.2.4.1 Five Electrode Pad Setup Screen
  • [0447] 6.3.1.2.2.4.2 Matrix Electrode Pad Setup Screen
  • [0448] 6.3.1.2.2.4.3 Single Electrode Pad Setup Screen
  • [0449] 6.3.1.3 Unconventional Defibrillation Methods
  • [0450] 6.3.1.4 Paths From Main Defibrillation Screen
  • [0451] 6.3.2 Anti-Tachycardia Pacing Screen
  • [0452] 6.3.2.1 General Considerations
  • [0453] 6.3.2.2 Default Values
  • [0454] 6.3.2.3 Non-Default Values
  • [0455] 6.3.2.4 Paths from Anti-Tachycardia Pacing Screen
  • [0456] 6.3.3 Bradycardia Pacing Screens
  • [0457] 6.3.3.1 Paths to Main Pacing Screen
  • [0458] 6.3.3.2 Method of Operation: Bradycardia Pacing Screens
  • [0459] 6.3.3.2.1 Default Values
  • [0460] 6.3.3.2.1.1 Common versus Different Parameters for Bradycardia Pacing and for Anti-Tachycardia Pacing
  • [0461] 6.3.3.2.2 Non-Default Values
  • [0462] 6.3.3.2.2.1 Pacer Amplitude Screen
  • [0463] 6.3.3.2.2.2 Bradycardia Pacing Rate Screen
  • [0464] 6.3.3.2.2.3 Pulse Shape Screen/Pacing
  • [0465] 6.3.3.2.2.4 Electrode Setup Screens/Pacing
  • [0466] 6.3.3.2.2.5 Pacemaker Sensing
  • [0467] 6.3.3.2.2.5.1 Sensing from the Electrode Arrangement with the Largest R-Wave
  • [0468] 6.3.3.2.2.5.2 Sensing from the Electrode Arrangement used for Pacing
  • [0469] 6.3.3.2.2.5.3 Sensing from an Electrode Arrangement Selected by the MP
  • [0470] 6.3.3.2.3 Termination of Pacing
  • [0471] 6.3.3.3 Paths from Main Pacing Screen

[0472] 6.4 MP-Directed PU Diagnostic Check and Maintenance Screen

[0473] 6.5 Master Triage Screen

[0474] 6.6 Main Screen Menu

[0475] 6.7 Command Confirmation and Event Log

7. Block Diagrams: Units and Major Components of the System

[0476] 7.1 The Portable Unit

[0477] 7.2 The Stationary Unit

[0478] 7.3 The Master Control Unit

[0479] 7.4 The Central Station

[0480] 7.5 The Stationary Unit Decoder

[0481] 7.6 The Portable Unit Decoder

[0482] 7.7 The Portable Unit Encoder

[0483] 7.8 The Central Station Decoder

[0484] 7.9 The Central Station Encoder

8. Miscellaneous

[0485] 8.1 Diagnostic Check

[0486] 8.2 Universal Connectors

[0487] 8.3 Network of Central Stations

[0488] 8.4 Multiple Communication Modalities and Routes

[0489] 8.5 Multiple Possible Routes and Relays Between PU and CS

[0490] 8.6 Control of an Implantable Cardioverter-Defibrillator by the MP

[0491] 8.7 Defibrillation Using Two or More Different Shocks in One Victim

[0492] 8.8 Monitoring Adequacy of Ventilation During Resuscitation Using Pressure and/or Flow Monitoring

[0493] 8.9 Monitoring Adequacy of Ventilation During Resuscitation Using Transthoracic Impedance

[0494]

TABLES
1)	Master Control States	1.3.1.2
2)	Summary of Figures	1.4
3)	ECG Recording Configuration on Five	3.2
	Electrode Pad
4)	ECG Recording Configuration on Five	3.2
	Electrode Pad with Seven Sensing
	Electrodes
5)	ECG Recording Configuration on	3.3
	Thirty Two Electrode Pad
6)	Seven Phases of Activity During A	4.1
	Cardiac Arrest
7)	Four Layers of Handshake Linking	4.1.2.1
	Enabler and MP
8)	PU-CS Routing Analysis and Backup When	4.1.2.4.1
	SU is Available
9)	Four Layers of Handshake Linking	4.1.3.2.1
	Victim and MP
10)	Four Layers of Handshake Linking	4.1.6.2
	EMT and MP
11)	Events During an Hypothetical Cardiac	4.2
	Arrest
12)	Deployment of the Old PU after EMT	4.5.7.1.2
	Arrival
13)	Communication Choices Using the Second	4.5.7.5.2.2
	PU as a Relay
14)	Flow Diagrams of Events During a
	Cardiac Arrest
15)	Central Station Screen Summary
16)	Signals During Communication (Layer #1) Handshake
17)	Testing During Data/Commands (Layer #2) Handshake
18)	Testing During Audio (Layer #3) Handshake
19)	Testing During Enabler-MP Handshake:
	Which Tests are Abnormal for Each Component Failure
20)	Options for Communications Enhancement During the
	Four Handshakes of the Enabler-MP Link

1) Voice Prompts

2) Abbreviations

1. System Overview

[0495] In the text hereinabove and hereinbelow, both of the terms “medical emergency” and “cardiac arrest” are used to describe the event for which the invention may be used. A cardiac arrest is one type of medical emergency in which collapse occurs because the heart's electrical or mechanical function is severely abnormal. The initial heart rhythm during a cardiac arrest is usually either ventricular fibrillation (VF), ventricular tachycardia (VT), bradycardia or asystole; Occasionally, the rhythm is normal (pulseless electrical activity). A cardiac arrest can be diagnosed when the electrocardiogram of the victim of a medical emergency shows VF, VT, asystole or profound bradycardia. Certain types of bradycardia, VT and other tachycardias may constitute medical emergencies, although they may not be associated with complete collapse, and thus may not be considered to be cardiac arrests. Certain types of collapse, such as pulseless electrical activity, may constitute a medical emergency even though they may be associated with a normal heart rhythm; The absence of a palpable pulse and/or measurable blood pressure is required for this diagnosis.

1.1 Description of the Emergency Scene

[0496] FIG. 1 shows an overview of the scene of a medical emergency scene 10 during the moments after the victim is first observed. In this preferred embodiment of the invention, an enabler 100, i.e. a person who observes a victim of a medical emergency 102 and wishes to participate in the resuscitation of said victim, begins the process by pressing emergency button 106 (hereinafter referred to as “button press”) on portable unit 104. Victim 102 may be conscious or unconscious. Enabler 100 is a person with no prior medical or emergency training.

[0497] By pressing the button, the enabler 100 causes the portable unit to establish a communications link with a central station 300 in which highly skilled personnel are situated. A medical professional 301 then guides enabler 100 through a series of steps, each of which requires no medical expertise on the part of enabler, that will allow the medical professional to diagnose and, if necessary, directly control resuscitative maneuvers on victim 102 via portable unit 104. Such maneuvers include defibrillating or pacing the heart. Communication between the scene of the medical emergency and the central station may be via a telephone system 114 (either copper-based, optical fiber based, radio frequency based, or hybrid), or via radio frequency link 116 (either direct, with repeaters, with satellite linkages or a hybrid system). The presence of backup and/or redundant communication modalities, results in a highly robust link between the scene of the emergency and the central station. However, in the event that all communication systems fail, a backup automatic defibrillation system allows continued operation of the system.

[0498] Referring to FIG. 2A, in the preferred embodiment, portable unit 104 is attached to stationary unit 108, which is anchored to a wall. Emergency button 106 is labeled in a manner which allows enabler 100 to easily and rapidly discern that it is to be pressed in the event of a medical emergency. It may, for instance, have a large red cross on its surface. It may have the words “Medical Emergency” or “Press Button for Medical Emergency” or other similar wording on its surface or immediately adjacent. The words would be plainly visible from a distance.

[0499] Portable unit 104 and stationary unit 108 may be situated in any public place such as an airport, a shopping mall, a gambling casino, a restaurant, etc. Alternatively these units may be situated in non-public places such as a person's home or an office. Another alternative would involve the placement of such units within a medical facility, e.g. a hospital, nursing home or rehabilitation facility.

[0500] Pressing emergency button 106 causes communication between the portable unit and the central station to be quickly established. Immediately following an initial electronic handshaking process, the central station is automatically informed of the exact location of the portable unit. The medical professional then identifies himself to the enabler 100, and confirms that both the medical professional and enabler 100 can hear and understand each other. The medical professional then inquires as to the nature of the situation that enabler 100 has observed. If the medical professional decides that the resuscitative equipment contained in portable unit 104 will be useful for the resuscitation of victim 102, the medical professional will cause a lock to release the portable unit 104, from the stationary unit, 108. The medical professional will tell enabler 100 to detach portable unit 104 from stationary unit 108 by grasping handles 110, and to quickly carry the portable unit 104 to the victim's side.

[0501] FIG. 2B is another overview of the system, showing the scene of the medical emergency after the medical professional has released the portable unit and instructed the enabler to transport it to the victim's side. The portable unit 104 is situated immediately adjacent to the victim 102. Electrode pad 200 has been attached to the chest of victim 102. The electrode pad 200 allows a medical professional to observe the victim's electrocardiogram, and to control the application of electrical energy to the victim, for either pacing, cardioverting or defibrillating the heart. The electrode pad 200 is initially situated within a storage compartment of portable unit 104. Detailed instructions describing removal of the electrode pad 200 from the portable unit 104 and describing the process of application of the electrode pad 200 to the chest of victim 102 will be provided to enabler 100 by the medical professional. Electrical energy is conveyed between electrode pad 200 and the portable unit 104 by a cable 202 which consists of multiple insulated wires.

[0502] The medical professional's ability to instruct the enabler 100 in the proper application of the electrode pad 200 to the victim 102 is enhanced by medical professional's being able to see the victim 102 and to observe the enabler's application of the electrode pad 200. The medical professional observes the scene via a television camera which may be built into the portable unit 104. Video apparatus is contained within a video boom 112, which may be extended from the portable unit 104, and pointed in any direction. The video apparatus may include one or more lenses and means for remote focusing. It may further include means for collecting light and amplifying it. The projection 112 may be moved in three dimensions by either enabler 100 or the medical professional, via telemetry signals between the central station and the portable unit 104.

[0503] Enabler 100 may be instructed in additional maneuvers by the medical professional. These include various forms of circulatory and/or respiratory assist for victim 102 including cardiopulmonary resuscitation.

[0504] Portable unit 104 communicates with central station either directly, or indirectly via stationary unit 108. FIG. 2b shows a radio frequency link between portable unit 104 and stationary unit 108, but other types of link are possible including infrared light based or hard-wiring.

1.2 Description of the Central Station

[0505] FIG. 3 shows a view of the medical professional's console or control panel. The medical professional 301 sits with easy access to multiple video displays, inputting devices and communication systems. These allow the medical professional to evaluate the victim, treat the victim, and communicate with the enabler, who is instructed by the medical professional. The video displays allow the medical professional to observe the physiologic status of the victim of a medical emergency, to have access to other data relating to the current medical event and prior medical events for this victim, to have access to signal quality and communication options, access to triage status and triage options and access to higher echelons of advice, either from a computer-based expert system, or from a super-expert medical professional. The inputting devices allow the medical professional 301 to directly control various aspects of the management of the medical emergency such as defibrillation and pacing of the heart. They also allow him to control the communications link with the portable unit and enabler. They also allow the medical professional 301 to provide audio and video instructional information for the enabler.

[0506] The victim's electrocardiogram is displayed on screens 302. Many different display formats are possible including one, two or multiple simultaneous electrocardiogram leads, as well as the ability to freeze and hold a tracing on one screen (for reference or for further analysis), while continuing to view “live” electrocardiograms on another screen. The victim's blood pressure data is displayed on screen 304, and oxygen saturation data is displayed on screen 306. Other parameters of respiratory status, blood sugar, body temperature and other physiologic parameters may also be displayed.

[0507] The medical professional 301 may observe the victim and the performance of the enabler at the emergency site on screen 308. The medical professional 301 controls the field to which he has video access by manipulating the video boom 112 of the portable unit 104. The length and orientation of the video boom may be controlled by the medical professional using joystick 310. The medical professional 301 may also control the video boom via the keyboard 312, the mouse, 314, or via a touch sensitive screen.

[0508] In a preferred embodiment of the system, the medical professional's carries on an audio dialog with the enabler, and possibly other medical professionals including emergency services local to the victim and including higher level medical experts. The medical professional's voice is picked up by microphone 316, mounted near said medical professional. Alternatively the medical professional may wear a lapel-type microphone, may wear a headset containing a microphone, or may use telephone handset 318. The medical professional hears the voice of the person with whom he is communicating via either speakers 320, earphones, a headset containing earphones plus microphone, or telephone handset 318.

[0509] If audio communication is not effective for any reason, the medical professional has the option of transmitting and receiving text messages to and from the enabler. Keyboard 312 may be used to input text messages. The message, as displayed to the enabler can be seen by the medical professional on screen 322. Text messages from the enabler are viewed by the medical professional on screen 324, and may be printed by printer 326. Printer 326 may also be used to print other data including electrocardiograms, other physiologic data, archived information about the victim's medical history, communications information and/or a complete log of the current medical event. In the event of complete failure of communications, the portable unit's automatic external defibrillation circuits (see below) would allow resuscitative efforts to proceed.

[0510] In a preferred embodiment, the medical professional inputs commands which control electrical therapy to the victim including defibrillation and pacing. Each of the parameters which control these processes (e.g. pulse energy, pulse width, synchronization) may be selected by the medical professional. One means of selection is via touch sensitive screens 328, 330, 332, and 334. A menu of possible choices is displayed on the touch sensitive screen. The medical professional selects his choice by touching the appropriate spot on the screen with either his finger or a wand. Alternatively, such choices can be made by moving the mouse which moves a pointer on the screen(s), and by clicking over the appropriate choice. The medical professional may also input commands via keyboard 312, using either the arrow keys to navigate among choices displayed on the screen, or by directly inputting commands that are alphabetic (e.g. “control S” for shock) or numeric (e.g. “100” for shock energy), or by using the “f keys.” The medical professional my also input commands by voice, using a voice recognition system.

[0511] Since the number of possible menus and displays may exceed the number of video screens, the medical professional may select the content of each screen by accessing a screen menu. The screen menu lists all possible (touch-sensitive) sub menus and (non-touch-sensitive) displays. The medical professional uses the screen menu to assign a sub-menu or a display to each screen. FIG. 3 shows one such assignment.

[0512] Passive screens 336 and 338 are not touch sensitive and are used to display information. Examples of such screens would include the event log, communications information and the victim's medical history.

[0513] Screens 322 and 324 are identical in display content to the corresponding two screens on the portable unit 104, This allows the medical professional to view exactly what the enabler 100 is viewing. Besides text messages, these screens may be used, at the direction of the medical professional, to display instructional videos for the enabler, or, a live video of the medical professional, for purposes of reassurance or instruction.

[0514] In the event that the enabler is himself a medical professional, electrocardiograms or other physiologic data, and defibrillator and pacing control screens may be enabled, and displayed on screens 322 and 324.

[0515] The medical professional 301 may receive advisory prompts, shown in FIG. 3 on the lower portion of screens 330 and 332. Such prompts may include expert system based suggestions for medical management, changes in a physiologic parameter noteworthy enough to bring to the immediate attention of the medical professional, changes in communications status, changes in triage status, or changes in the operating integrity of any part of the system.

[0516] The current time is displayed on screen 340; the elapsed time, from the start of the emergency call is displayed on screen 342. Other time intervals, including time since definitive therapy begins, or elapsed time starting with the estimated moment of the victim's collapse, may also be displayed.

[0517] Many other display arrangements are possible, including those with different numbers of screens, different geometric arrangements of screens and different inputting devices.

[0518] An on site data storage system 344 allows the medical professional to have access to patient databases, pacemaker and implantable defibrillator information, drug information, expert system programs for management of medical emergencies and information about local emergency response teams around the world. It also allows for storage of data pertaining to the current medical emergency.

1.3 Block Diagram of the System

1.3.1 Two Unit System: PU and Central Station

1.3.1.1 System Operation When PU-CS Communication Is Intact

[0519] FIG. 4A is a diagrammatic overview of the system, showing greater detail than FIG. 1. It shows the flow of information (including the medical professional's control of defibrillation and pacing) within the system, after it has been attached to the victim 102. To simplify the presentation, FIG. 4A shows an embodiment of the system in which the portable unit 104 communicates directly with the central station 300, without a stationary unit 108 interposed between. FIG. 4B is analogous to FIG. 4A, but it includes the stationary unit.

[0520] Referring to FIG. 4A, portable unit 104 obtains the ECG and other physiologic data from the victim 102. These signals are amplified, filtered, digitized and processed by ECG and physiologic data processing unit 118.

[0521] Processing unit 118 has three outputs: a) to the PU encoder 120; b) via <AA> to “AED/P,” the automatic external defibrillator/pacer analysis, logic and control unit 128; and c) via <AA> to defibrillator and pacing control circuits 131. The signals from data processing unit 118 to the PU encoder 120 (described in detail below) are encoded and transmitted to the central station 300 by portable unit transmitter 122. The portable unit transmitter may output into either a public telephone network, the Internet via public telephone network, or a private communication system, either hard-wired, radio frequency, or hybrid. The signals from data processing unit 118, via <AA>, are used by the AED/P analysis, logic and control unit 128 which automatically controls defibrillation and pacing, in the event of communications failure between the PU and the CS. The signals from data processing unit 118, via <AA> to the defibrillator pacing and control circuits 131: a) may be used to provide a synchronization (timing) signal for defibrillation and b) is used to provide inhibitory signals if pacing is performed for bradycardia.

[0522] Referring again to inputs to the PU, audio input signals including the voice of enabler 100 and video input signals showing the victim and the scene of the emergency are amplified, filtered, digitized and processed by the portable unit audio and video input processing units 124. The audio and video data is then encoded by portable unit encoder 120, and then transmitted by portable unit transmitter 122.

[0523] Central station 300 receives information sent by the portable unit via central station receiver 346. The receiver can receive either radio frequency or hard-wired signals. The signals are decoded by central station decoder 348 (described in detail as FIG. 53). The decoder supplies ECG and physiologic data signals which are processed by the ECG and physiologic data processing unit 350 and displayed on the appropriate screens (302, 304 and 306, in FIG. 3) for viewing by the medical professional 301. The decoder output also supplies audio and video information which is processed by the central station audio and video output processing units 352, and thus heard and seen by the medical professional 301.

[0524] Using the ECG data, the medical professional can diagnose an abnormal heart rhythm in a victim. In the event that the victim has suffered a cardiac arrest, the medical professional can cause the portable unit to supply a defibrillating shock to the victim. Lesser degrees of abnormality can also be diagnosed and treated by the medical professional. The medical professional would defibrillate a patient by selecting each of a number of parameters including shock energy, pulse configuration, the particular electrodes of the defibrillator pad through which energy is to pass (see ahead), and timing of shock. The value or choice for each of these parameters would be inputted by the medical professional through any of a variety of input devices (shown in FIG. 3) including touch sensitive screens 328, 330, 332 and 334; keyboard 312, or mouse 314. The command signals are processed by command signal processing unit 354. These signals are then encoded by the central station encoder (described separately in FIG. 54) and then transmitted by the central station transmitter 358. The central station transmitter may interface with a variety of communication systems, as is the case with the portable unit transmitter 122, described previously.

[0525] The medical professional accomplishes a number of desirable goals by speaking with the enabler. These include:

[0526] a) carrying on an initial dialogue with the enabler to assess whether these is an emergency and whether use of the portable unit 104 is appropriate;

[0527] b) supplying instructions for properly transporting the unit and setting it up at the side of the victim;

[0528] c) supplying instruction for properly placing a defibrillation pad on the chest of the victim;

[0529] d) informing the enabler and other bystanders to avoid contact with the victim at the moment of a defibrillation shock;

[0530] e) instructing the enabler in cardiopulmonary resuscitation;

[0531] f) instructing the enabler to obtain, if possible, identifying information about the victim (to facilitate patient database access);

[0532] g) prompting the enabler to supply neurologic information, specifically, the enabler's assessment of the state of consciousness or responsiveness of the victim; and

[0533] h) reassuring the enabler and other bystanders, since a cardiac arrest situation is often attended by a certain degree of pandemonium and chaos.

[0534] The medical professional's audio and video inputs are processed by the central station audio and video processing unit 360. After amplification, filtering, digitization, formatting and other signal processing, these signals are passed to the central station encoder 356, and then transmitted by the central station transmitter 358 along with command signals. Central station video inputs include instructional materials related to pad placement and the correct performance of cardiopulmonary resuscitation. Allowing the enabler to see the medical professional, though not medically necessary may, in some cases, provide a measure of reassurance for an anxious enabler, and/or during a difficult resuscitation effort.

[0535] Audio and video information transmitted by the central station is received by the portable unit receiver 126, decoded by decoder 127, and amplified and processed by the portable unit audio and video output processing unit 134. This unit drives speakers and/or headphones, and a video display for enabler.

[0536] The medical professional's commands for: a) the master control unit 130; and b) the portable unit defibrillator and pacing control circuits 131, are received by portable unit receiver 126 and decoded by portable unit decoder 127. As long as communication between the central station and the portable unit is intact, commands from the central station, outputting from decoder 127 are passed through master control unit 130 to defibrillator and pacing control circuits 131. Control circuits 131 control defibrillator and pacing output circuits 132, the medium voltage (used for pacing) and high voltage (used for defibrillation) generating apparatus within the portable unit. Specifically, defibrillator and pacing control circuits 131 control all aspects of defibrillation pulse production including onset of capacitor charging, timing of discharge, pulse amplitude, shape and energy. If pacing (a medium voltage repetitive electrical stimulation) is necessary, circuits 131 control the pacing rate and mode, as well as pulse amplitude, shape and energy. The defibrillator and pacing output of the unit is coupled to the victim via cable 202 and electrode pad 200.

1.3.1.2 AED Backup in the Event of Communication Failure; Role of Master Control Unit

[0537] In the event of a failure of communication between the portable unit 104 and the central station 300, the portable unit may utilize automatic external defibrillator/pacer analysis, logic and control circuits 128, instead of commands from the medical professional, for control of PU electrical therapy. Automatic external defibrillators, AED's, as they are known in the art, contain circuits which analyze electrocardiogram signals, and, if ventricular fibrillation is detected, apply a high voltage shock to the victim of a cardiac arrest. They can provide pre-programmed voice prompts, for user instruction.

[0538] There are two situations which would result in transfer of control of defibrillation from the medical professional to the AED/P within the PU. The first such situation is in the event of failure of communications in either direction (or both directions) between the portable unit and the central station. In a preferred embodiment of the invention, a complex system of handshakes between the PU and the CS, described below, is used to constantly monitor the integrity of communications. The second such situation is in the event that the MP decides that the quality of the communication link is inadequate. At such time, he may send a control signal which transfers control of the PU to the AED/P.

[0539] Control of pacing and defibrillation is via the master control unit 130. The master control unit is, at all times, in one of five possible states. The particular state that it is in, determines who or what will control the major functions of the portable unit. Under normal operating conditions, the PU is controlled by the medical professional. But under certain circumstances, it becomes desirable to allow control by either the AED/P in the PU, or by an on-scene emergency medical team, or “EMT.” (Hereinafter EMT will be used to refer to both the entire emergency medical team and an individual member of the team who may communicate with the MP and who may be given access to PU control. EMT may also refer to a physician or other highly qualified person at the scene of the cardiac arrest.) Functions controlled by the master control unit 130 include high voltage charging and delivery and release of the PU locking mechanism. The matrix which shows the relationships between: a) master control unit state; b) who or what is in control; and c) which functions are subject to this control is shown in table 1, and described below.

[0540]

TABLE 1
Master Control States
		Charge	Deliver		Control
Master	PU	High	High		Of PU	Lock
Control	Control	Voltage	Voltage	AED/P	by TSS	Release
State	By	Enable	Enable	Enable	Enable	Enable
0	MP	No	No	No	No	No
1	MP	Yes	Yes	No	No	Yes
2	AED/P	Yes	Yes	Yes	No	Yes
3	EMT	Yes	Yes	No	Yes	Yes
4	MP	Yes	No	No	No	No

The state of the master control unit determines whether defibrillation and pacing are controlled by the MP, by the AED/P circuits, or by an on-scene emergency medical team. State 0 is the quiescent state, in which the PU remains, until activated when an enabler presses the emergency button 106. If, after enabler describes the emergency to the MP, the MP decides to release the PU, MP sends a command to the PU which causes master control unit 130 to enter state 1. In state 1, high voltage charging and delivery is enabled, and lock release is enabled. In the event that proper communication between the MP and the enabler can not be established or maintained, the master control unit enters state 2. In state 2, lock release no longer requires MP approval, and the PU functions as an AED/P. If a qualified Emergency Medical Team arrives, the MP may transfer control of the PU to the EMT by sending a command to the PU which causes the master control unit to enter state 3. In state 3, the EMT controls the PU by selecting commands on the PU touch sensitive screen, “TSS,” in much the same way that the MP would. Master control state 4 (see Sections 4.5.7.4.4 and 4.6.2), is entered when a diagnostic check of the PU is performed. In state 4, although the high voltage circuits may be charged, high voltage may not be delivered.

[0541] The AED/P analysis, logic and control unit 128 receives ECG information from ECG and physiologic data input processing unit 118 (described above) via <AA>. If VF is detected and if the master control unit has enabled control of defibrillation and pacing by the AED/P, the AED/P control unit 128 would have access to defibrillator and pacing control circuits 131. In this situation, a defibrillation control signal from the AED/P unit 128 would be relayed through master control unit 130 and cause defibrillator and pacing control circuits 131 to cause defibrillator and pacing output circuits 132 to provide a shock to the victim. The AED/P unit 128 also provides pre-programmed audio instructional information, which is amplified and processed by audio and video output unit 134.

1.3.2 Three Unit System: Portable Unit, Stationary Unit and Central Station

[0542] In the aforementioned embodiment, the portable unit and the central station communicate directly. In a preferred embodiment of the invention, the portable unit and the central station communicate via a stationary unit, 108, as shown in FIG. 4B. This three-unit arrangement allows for a portable unit with a less sophisticated receiver, and a less powerful transmitter. It will enhance the ability of the portable unit to remain in communication with the central station, even when operating deep inside of a building or other structure where electromagnetic wave propagation from the outside may be significantly attenuated.

[0543] As shown in FIG. 4B, the stationary unit functions as a repeater, consisting of two receivers and two transmitters. Stationary unit short-range receiver 136 receives signals from the portable unit transmitter 122. The information contained in these signals is transmitted by stationary unit long-range transmitter 138 to central station receiver 346. As was the case with the two unit system described in FIG. 4A (in which the portable unit communicated with the central station without an intermediary stationary unit), in the three-unit system described in FIG. 4B, the stationary unit long range transmitter 138 may output into either a public telephone network, the Internet via public telephone network, or a private communication system, either hard-wired, radio frequency, or hybrid.

[0544] Signals sent by the central station transmitter 358 are received by the stationary unit long-range receiver 140. Communication modalities for CS transmitter 358 and SU long-range receiver are similar to those previously mentioned for the SU long-range transmitter 138 and CS receiver 346. The information contained in these signal is transmitted by the SU short range transmitter 142 to the PU receiver 126 using a communication modality similar to the link between the PU transmitter 122 and the SU short range receiver 136.

[0545] The medical professional can control routing of signals between the stationary unit and the central station. In particular, he can control which of a multiplicity of communication options are used for these links. This process includes the transmission of routing control signals from the CS transmitter 358 to the SU long range receiver, from whence they are decoded by SU decoder 144 (described below).

[0546] Other communication options under the control of the MP include:

[0547] a) the option to switch from a three unit system (i.e. a system which includes the SU) to a two unit system (PU and CS, without SU) while the system is in use;

[0548] b) the option to switch from a two unit to a three unit system while the system is in use;

[0549] c) the control of the communications link (e.g. public telephone network, private network, radio frequency, Internet, etc.) between the SU and the PU (This process includes the transmission of routing control signals from the CS transmitter 358 to the PU long range receiver, from whence they are decoded by PU decoder 127 [described below].); and

[0550] d) the option to allow communication control (viz. the aforementioned choices involving routing and selection of communications modality) to be: (i) automatic (i.e. performed by the system), (ii) manual (i.e. performed by the MP), or (iii) a hybrid involving automatic control with the option of manual override.

1.4 Figure Assignments

[0551] The figure assignments for the overviews of the system, as well as all other figures is shown below, in Table 2.

[0552]

TABLE 2
Summary of Figures
FIG.	Subject
Overviews
1	System Overview
2A, 2B	Emergency Scene Overviews
3	View of Central Station
4A, 4B	Block Diagrams of Flow of Information among
	PU, SU, CS; Enabler, Victim and Medical
	Professional
Electrode Pads
5A-G	Views of Defibrillating/Pacing Pads
	Portable and Stationary Unit Hardware
6-11	Views of Portable Unit and of Stationary
	Unit
Flow Diagrams:
Four Handshakes Comprising Enabler-MP Link
12	Communication Handshake - PU component
13	Communication Handshake - CS component
14	Data/Commands Handshake
15	Audio Handshake
16	Informational Handshake and PU Lock Release
Flow Diagrams:
Portable Unit Deployment
17	Transport of PU to victim
18	PU Setup at victim's side
Flow Diagrams:
Arrhythmia Management
19	Arrhythmia Diagnosis
20	VF Treatment
21	Second Tier Arrhythmia Treatment
22	Anti-Tachycardia Pacing
23	Bradycardia Treatment
Flow Diagram:
Confirmation Signals
24	MP Command Execution and Confirmation, and
	PU Telemetry
CS Screens
25-44	Control Screens for Medical Professional
Block Diagrams:
Units and Major Components of the System
45-49	Portable Unit, Stationary Unit and Central
	Station: Block Diagrams
50-54	Decoders and Encoders: Block Diagrams
Miscellaneous
55A-B	Diagnostic Check: Block Diagram
56A-F	Universal Connectors (Pads to
	Portable Unit)
57	Network of Central Stations: Block
	Diagram
58	Communication Options
59	Signal Routing: Block Diagram
60	Control of ICD via CS
61	Resuscitation with Two Defibrillators
62	Resuscitation with Pressure and Flow Monitoring
63	Transthoracic Impedance Monitoring

2. Portable Unit and Stationary Unit: Exterior Elements
2.1 Portable Unit: Front and Right Side Panels

[0553] FIG. 6A shows the portable unit 104 attached to the stationary unit 108, as would be the case prior to removal of the portable unit by an enabler. Emergency button 106 is conspicuous, plainly visible from a distance. Handles 110 facilitate enabler's detachment of the PU from the SU, and enabler's carrying the PU to the victim's side.

[0554] Speakers 146 allow the enabler to hear the MP's voice. They may be situated in any one of a number of different geometrical arrangements, and their number may vary from a single speaker, to one or more on one or more faces of the PU. In general, their location would optimize enabler hearing, regardless of how the PU is put down and oriented at the victim's side. One or more microphones 148 are similarly placed to allow the MP to hear enabler, regardless of PU orientation. Telephone handset 150 may be optionally used by enabler in a noisy environment or if he is hard of hearing. The decision to use it may be made by the enabler himself, or at the suggestion of the medical professional in the central station. The handset is in electrical communication with the PU communication system via multi-wire cable 152. {Alternatively, the handset may have a wireless link to the PU.}

[0555] A female telephone jack 153 on the PU allows it to receive information from another PU (see Section 4.5.7.5.2.2). A female telephone jack 155 on the SU allows it to receive information from another PU (see FIG. 9 and Sections 4.5.7.5.1 and 4.5.7.5.2.2).

[0556] Video camera 154 allows the medical professional to view the environment of the portable unit. Before the unit is activated by the enabler, the outer optical surface of the camera is flush with the surface of the PU. However, the viewing apparatus is deployed on an extensible boom (112 in FIG. 2B; also well seen in FIG. 6B). The boom can be extended from the unit, and aimed in any direction, under the control of the medical professional. Video input from the portable unit allows the MP a number of advantages including:

[0557] a) the ability to observe anyone who presses emergency button 106; this will (i) act as a deterrent to inappropriate or prank activation of the unit, and (ii) allow the MP to more easily determine when such a prank activation is occurring;

[0558] b) the ability to instruct the enabler in the placement of electrode pad(s), by either (i) verbally instructing the enabler as he applies the electrode pad(s), or (ii) visually instructing the enabler by showing him a live video of the victim's torso, upon which MP has superimposed visual prompts such as arrows, an outline of the pad, or a cartoon version of the pad;

[0559] c) the ability to observe whether enabler has correctly placed electrode pad(s) 202 (FIG. 2B);

[0560] d) the ability to instruct the enabler in other resuscitation related acts, including cardiopulmonary resuscitation by either (i) verbally instructing the enabler as her performs these maneuvers, or (ii) visually instructing the enabler by showing him a live video of the victim, upon which MP has superimposed visual prompts appropriate for the maneuver;

[0561] e) the ability to observe the victim; and

[0562] f) the ability to observe the portable unit itself; this would be accomplished by extending the boom outside of the unit, and causing the boom to angulate at one or more points along its shaft, so that the net effect is a 180 degree reversal in the angle at which the camera is oriented; this would allow intermittent inspection of the unit by the MP.

[0563] Portable unit video screens 156 allow the user of the portable unit to view video information. As mentioned previously such information includes: a) text messages from the MP, in the event that the enabler can not hear the MP's voice; b) instructional video regarding (i) correct electrode pad placement and orientation, and (ii) proper execution of various maneuvers including cardiopulmonary resuscitation; and c) the medical professional.

[0564] In one embodiment of the invention, one or more of the screens would be touch sensitive. In the event that the MP can not properly hear the enabler, the MP may instruct the enabler to respond by touching virtual buttons on the screen with labels such as “yes” and “no”. Alternatively, other potential answers to MP questions may be displayed as virtual buttons. Alternatively, a virtual keyboard may be displayed, to allow enabler to make a more detailed textual response.

[0565] Finally, in the event that the enabler is replaced at some point during the emergency by an EMT, it will be possible to allow the EMT to: a) view the victim's electrocardiogram; and b) have access to control of defibrillation and pacing by making one or both of screens 156 touch sensitive. In this situation, the medical professional in the central station, upon receiving evidence that the EMT is properly identified and or qualified, would send a command to the PU (See discussion of master control, ahead; Also see Table 1.) which would enable control of the PU via the touch sensitive screens and display the victim's electrocardiogram on these screens. The two screens on the PU would then function in a manner analogous to the control panel in the central station.

[0566] There are many possible ways in which the screens may be arranged geometrically. There may be one or more screens, or none. Finally “screen-in-screen” and split screen displays are possible.

[0567] Door 158 covers a tool-kit, the contents of which are visible in FIGS. 7A and 7B. The door is locked until either: a) the MP releases it; or b) the PU is detached from the SU and placed down on the ground or other firm surface. Knob 160 facilitates enabler's opening of the door, once it has been released.

[0568] Antenna 162 allows the PU to be in radio communication with the SU. The antenna may be fixed in length, extendible (and retractable) manually, or extendible (and retractable) in response to a command by the MP. It may be contained entirely within the PU housing at all times; or it may lie partially or fully outside of the PU housing at all times; or it may, prior to the emergency, be situated entirely within the PU and be extended outside of the housing during the emergency, at the discretion of the MP. The antenna may also allow communication directly with the central station, i.e. without doing so via the SU. More than one antenna may be used to optimize communications over a wide range of frequencies.

[0569] Antenna 164 allows the SU 108 to be in radio communication with the PU 104. The antenna may be fixed in length, extendible (and retractable) manually, or extendible (and retractable) in response to a command by the MP. It may be contained entirely within the SU housing at all times; or it may lie partially or fully outside of the SU housing at all times; or it may, prior to the emergency, be situated entirely within the SU and be extended outside of the housing during the emergency, at the discretion of the MP. Either the same antenna or another one (with or without the same external control options as antenna 164) may be used to allow the SU to communicate via radio frequency with the CS. There may be additional SU antennas to optimize communications a) between PU and SU, and b) between SU and CS over a wide range of frequencies.

[0570] FIG. 6B shows portable unit 104 without stationary unit 108. It shows partial extension of the video boom 112. It also shows door 158 in the open position, revealing multiple shelves and compartments within the tool-kit.

2.2 Portable Unit: Tool-kit

[0571] FIG. 7A shows the contents of the tool-kit. Five compartments 166A-166E contain electrode pads of various shapes and configurations. Each one is already wired into the portable unit, and ready to be applied to the victim. The choice of which of the pads is to be used, is made by the medical professional. Element 168 is a headset with microphone, which may make it easier for either the enabler or the medical professional to hear, in a noisy environment. The headset-microphone unit may be wireless, or hard-wired into the portable unit. Element 170 is a pair of scissors, to be used by the enabler, if necessary, to cut the shirt or blouse of a victim, in order to allow rapid placement of the electrode pad against the skin of the victim. Element 172 is a blood pressure cuff. It is of the automatically inflating and recording variety, as is known in the art. Upon instruction by the medical professional, enabler places it around the arm of a victim, allowing the MP in the central station to have intermittent blood pressure readings. Element 174 is a pulse oximetry transducer and holder. Upon instruction by the MP, enabler places it around the finger of a victim, allowing the MP in the central station to determine the victim's arterial oxygen saturation. Element 176 is a telephone wire and jack. One end of the wire is connected directly to the PU, allowing it to have a hard-wired interface with the public telephone network. The free end of the wire, terminating in a male jack, may be used by the enabler or EMT to connect the unit to the public telephone network, in the event that wireless communication to or from the portable unit is inadequate. Compartment 177 contains one or more spare pads which terminate in Universal Connectors (see ahead) but which are not, while stored in compartment 177, wired into the system. Compartment 177 also contains any one or more of a variety of items, including spare items for any of the aforementioned tool-kit supplies, an oral airway, gloves, telephone cable extensions, an apparatus for measuring the victim's cardiac output, the data from which may be transmitted to the MP (along with other victim data), and apparatus to assist in providing respiratory support for the victim. It may also contain a variety of items to be used by a physician, nurse, emergency medical technician including medications, intravenous administration fluids and apparatus and a stethoscope.

[0572] FIG. 7B shows a side view of the upper five compartments 166A-166E of the tool-kit. Item 204 is a defibrillating pad which contains five large electrodes, and which may additionally contain seven small electrodes for recording the electrocardiogram. Cable 212A electrically connects the pad to the female version of the universal connector 218A (for the pad without ECG electrodes) or 218B (for the pad with ECG electrodes). This mates with the male version of the universal connector 220A, which is electrically connected to the portable unit via cable 222.

[0573] Electrode pad 206 is similar to pad 204, in terms of electrode content and configuration, but its shape has been modified to allow greater conformity to the female torso. It is connected by cable 212B to female universal connector 218B, which mates with male universal connector 220B, which is connected to the portable unit by cable 224.

[0574] Electrode pad 208 contains a matrix of 32 electrodes. It is connected by cable 214 to female universal connector 218C, which mates with male universal connector 220C, which is connected to the portable unit by cable 226.

[0575] Electrode pads 210 each consist of a single defibrillating/pacing electrode. They are connected by wires 216 to female universal connector 218D, which mates with male universal connector 220D, which is connected to the portable unit by cable 228. Pads 210 are easily distinguished from each other, by either color, numeric markings, alphabetic markings, or any combination of these. They would be selected at the discretion of the medical professional, and two or more would be positioned under the direction of the MP.

[0576] Mini-pads 211 are intended for placement on the extremities for recording the ECG, and are not used as defibrillating/pacing electrodes. They are to be used when the MP decides that there is no need for defibrillation or pacing. They could be used when a conscious victim either doesn't need or refuses to allow the placement of defibrillating/pacing electrodes on the torso. They are connected by cable 217 to female universal connector 218E, which mates with male universal connector 220E, which is connected to the portable unit by cable 229. Labels RA, LA, RL and LL on the mini-pads refer to right arm, left arm, right leg and left leg, the intended placement locations. The mini-pads could also be color or number coded.

[0577] Individual defibrillating electrodes 210 and ECG electrodes 211 are well known in the art, and hence no further description of these elements is necessary. Different shapes and numbers of these single pads are possible.

[0578] Cables 212A, 212B, 214, 216 and 217 are of sufficient length to extend from the portable unit to the victim. Universal connectors 218A-218E and 220A-220E would ordinarily remain inside of the portable unit tool-kit compartment during use. However, cables 222, 224, 226, 228 and 229 are of sufficient length so that pulling on cables 212A, 212B, 214, 216 and 217 exposes the universal connector pair, allowing an already used electrode pad to be easily replaced.

2.3 Portable Unit: Rear and Left Side Panel

[0579] FIG. 8 shows a view of the portable unit from the back, also showing the left side of the unit, i.e. the side opposite that which contains telephone handset 150. The back contains two or more sensor switches 178. These are push-button type switches, with a spring to keep the center dowel normally extended outwards. In the preferred embodiment, when the PU is not in use, the back of the PU is in close proximity to the outer surface of the stationary unit 108 (see FIGS. 6A and 9). This proximity results in the dowel of sensor switches 178 being pushed in. When the PU is removed from the SU, the spring-loaded dowel pops out, the sensor switch changes state, allowing the MP to know that the PU was removed from the SU. When the PU is placed on a surface such that its back faces down, the MP is once again notified, since sensor switches 178 will again change state as the dowel is pushed back in. And when the PU is later reconnected to the SU, the MP can gauge the adequacy of the reconnection procedure by the response of sensor switches 178.

[0580] The sensor switches may have more than two positions, allowing the MP to ascertain with greater accuracy whether the PU has been properly positioned during replacement. When three or more sensors are present, they may be distributed both horizontally and vertically, allowing the MP to have three dimensional information about the position of the PU as it is replaced, and thereby allowing the MP to more fully guide the person performing the PU replacement (see Section 4.5.7.4.3).

[0581] Four feet 180 allow the PU, once separated from the SU, to rest on a flat surface, with back side facing down, but without the back being flush against the flat surface.

[0582] In a preferred embodiment of the invention the PU, in its quiescent state, is locked to the SU. The SU is shown in FIG. 9. Receptacle and electromagnetic lock 182, FIG. 8, admits projection 194, FIG. 9 from the SU, to which it locks. This prevents removal of the PU from the SU by unauthorized persons. After the medical professional determines that a particular situation warrants the use of the PU, he sends a signal from the central station which causes the electromagnetic lock 182 to release its hold on projection 194.

[0583] In the event that either the lock release signal is not properly received or processed, or in the event of mechanical failure in the electromagnetic release mechanism, a backup, purely mechanical release mechanism is present. Combination lock and release mechanism 184 consists of a combination type lock, 184A as is known in the art. When enabler correctly turns its one or more wheels to the correct combination, he can push lever 184B which causes the release of projection 194. The combination would be made available to enabler by voice or text message, when appropriate. The combination lock and release mechanism are seen on the side of the PU opposite the side which contains telephone handset 150.

[0584] Embodiments of the invention without an SU are possible. Embodiments of the invention in which the locking projection 194 comes form a stationary object other than a stationary unit are possible; for example, the locking projection may be attached directly to a wall. Embodiments of the invention without a lock are also possible.

[0585] Embodiments of the invention with other backup lock release mechanisms are possible including: a) an electrical mechanism which actively releases the lock in the event of communications failure (locking mechanism normally closed); b) an electrical mechanism which passively releases the lock in the event of communications failure (locking mechanism normally open); and c) lock releases which include both mechanical mechanisms (the aforementioned) and electrical mechanisms (either (a) or (b)).

[0586] Element 186 is a power connector, which feeds electrical power into the portable unit. This source of power is used to operate the PU 104 and to charge its batteries, while it is in contact with the stationary unit 108. The PU power connector connects to the SU power connector 192, FIG. 9. Embodiments of the invention in which the PU receives electrical power directly from an alternating current source are possible. Embodiments of the invention in which the PU has long shelf-life batteries and does not have an alternating current supply are also possible.

[0587] Element 188, FIG. 8 is the PU telemetry connector which mates with the SU telemetry connector 190, FIG. 9. These telemetry connectors carry information between PU 104 and SU 108 before they have been separated. Such information includes audio and video signals, text messages and telemetry signals between the MP and the enabler. In a preferred embodiment of the invention, the SU serves as an intermediate communications link between the PU and the central station. Embodiments in which the PU may or must communicate directly with the central station are also possible. Such an embodiment may have an external male telephone jack (such as element 176 within the tool-kit) for attachment to the public telephone network.

[0588] The left side also contains a magnetic card reading device 185. This allows the MP to have access to the information on a card which may contain victim medical history. It also allows the MP to have access to information on a card which properly identifies EMT personnel, before control of the PU is transferred.

2.4 Stationary Unit: Front and Side Panels

[0589] The stationary unit 108 is L-shaped, allowing its lower portion to support the PU. Line cord and plug 196 allow for supply of outside power. Telephone cable and male jack 198 allow for connection of the SU to the public telephone network. Female telephone jack 155 allows the SU to receive a direct telephone connection from a PU. The SU may have four depressions in its surface, positioned where the PU feet 180 come in contact with it. These depressions are wide enough to admit the PU feet, and are of a depth that is less than the height of the PU feet. This allows the PU feet to partially penetrate the SU surface. This geometry, along with sensor switches 178 having more than two positions, allows the MP to distinguish:

[0590] a) when the PU has been detached from the SU by the enabler (all center dowels of switches 178 in the fully extended position); from

[0591] b) when the PU is placed properly on the ground or another level surface (all center dowels of switches 178 in the partially extended position); from

[0592] c) when the PU has been properly returned to its correct position on the SU shelf (all center dowels of switches 178 in the fully retracted position); from

[0593] d) when the PU is improperly positioned on the SU shelf (not all center dowels of switches 178 fully retracted).

2.5 Portable Unit: Screens

[0594] FIGS. 10 and 11 show various configurations for PU screens 156. (See FIG. 6A for frontal PU view.)

[0595] The left screen in FIG. 10 shows an instructional video. In the example shown, a cartoon 365 of the victim is seen along with cartoon designations of ideal electrode pad locations 366. Alternatively, the screen may show the actual victim 102, visualized by PU video camera 154; with superimposed markings or overlays, manipulated by the MP, indicating desired electrode pad placement. Alternatively, other instructional videos including techniques of cardiopulmonary resuscitation may be displayed. Alternatively, a video display of the medical professional in the central station may be displayed.

[0596] The right screen in FIG. 10 shows a text message from the medical professional 301 in the central station 300. Such messages may be utilized in the event of poor quality reception of CS signals at the PU, a noisy emergency scene, or a heard-of-hearing enabler.

[0597] FIG. 11 shows the use of the PU screens in a touch sensitive mode. The left PU screen shows a control panel similar to that utilized by the medical professional in the central station. This screen is displayed only under special circumstances. The MP can enable local (i.e. victim-side) control of the portable unit, in the event of arrival of trained medical personnel at the emergency scene, or if the enabler himself is a qualified medical professional. The MP enables EMT control of the PU by sending a command to set the master control unit 130 to state 3 (see Table 1, above). When EMT control is enabled by the MP, the victim's electrocardiogram tracing 367 is displayed. Virtual control buttons 368 on a touch sensitive control screen allow control of defibrillation, pacing, monitoring and other functions. The on-site professional would be able to access any of the portable unit control screens available to the central station medical professional.

[0598] The right screen in FIG. 11 shows a virtual keyboard 369, with a “YES” key 370, a “NO” key 371 and “hot-keys” 372. This screen allows the enabler 100 to send text messages to the medical professional in the event of poor quality audio reception of PU signals at the CS, or in the event of a noisy emergency scene.

[0599] The screen functions shown in FIGS. 10 and 11 need not occupy a full screen. Screen-in-screen and split screen displays are also possible.

3.0 Electrode Pads

3.1 Physiology of Defibrillation

[0600] The termination of ventricular fibrillation during a cardiac arrest is accomplished by passing a brief, high voltage pulse between two electrically conducting pads on a victim's chest. Since the success of the defibrillating pulse is dependent on the achievement of sufficient voltage gradient, over sufficient volume of heart tissue, proper positioning of the defibrillating electrodes is critical. If the electrodes are too close to each other, regions of cardiac muscle not near the electrodes will have insufficient voltage gradient, and the defibrillation attempt will be unsuccessful. Similarly, if the electrodes are not sufficiently near the heart, an unsuccessful defibrillation attempt may ensue.

[0601] Standard operating procedure for defibrillation calls for the passage of an electric current between two pads on the victim's chest, one placed high on the chest to the right of the midline, and one placed on the far left side of the chest, beneath the nipple. Alternate approaches involve a single electrode on the chest surface (generally referred to as anterior) and another electrode on the back (generally referred to as posterior.

[0602] In the preferred embodiment of the invention, the medical professional has access to more than two defibrillation electrodes. This allows the MP to select what he believes to be the optimum vector or pathway for defibrillation energy applications. If the first defibrillating shock is unsuccessful, the MP, when more than two defibrillation electrodes are present, would be able to change the pathway of defibrillation energy for a subsequent shock, by changing the choice of electrodes. The ability to change the choice of electrodes also allows the MP to compensate for inaccuracies in positioning and/or orienting the electrode pad. It also allows the MP to make adjustments for different victim sizes and different heart sizes.

3.2 Torso-Shaped Multi-Electrode Pads

[0603] FIG. 5A shows the non-victim side of a five electrode “pad” 204A It is torso shaped, with an extended portion, labeled “VICTIM'S LEFT” which is intended to wrap around the victims left side, that is, the victim's left axillary region, slightly below the level of the breast. Individual electrodes, as are known in the art, are located at 230, 232, 234, 236 and 238, each of which contains electrically conductive material on the patient side of the pad. A wire extends from each electrode; the five wires, though insulated from each other, coalesce to form cable 212A. Easily seen labels reading “NECK” and “VICTIM'S LEFT” are intended to help the enabler properly position the pad on the victim's torso.

[0604] The selection of defibrillating electrode location generally calls for having as much of the heart's mass lying on a direct path between the defibrillating electrodes. Therefore, the typical defibrillation effort would entail the application of energy between electrode 230, labeled α, located over the right upper torso; and electrode 236, labeled δ, located beneath the left breast. If such a shock did not result in the restoration of a normal rhythm, a second effort involving electrodes 230 (α) and 238 (ε) would be a reasonable choice. The α-ε pair might be a good first choice for a very large patient. This choice, and all other choices of electrodes would be made by the medical professional's selecting these electrodes from among a menu of options. With a five electrode pad, the MP may choose any of ten possible pairs of electrodes. (The value of ten ignores polarity considerations.) The MP may elect to apply energy when two or more electrodes are made electrically common. An example of this would be to make electrodes 236 (δ) and 238 (ε) electrically common, and to apply energy between electrode 230 (α) and the composite δ/ε electrode. In principle, the use of 3, 4 and 5 electrode combinations increases the number of possible electrode combinations 90. (The value of 90 ignores polarity considerations.). Although in practice, many of these 90 combinations would not be clinically sensible, some would be.

[0605] In the event that the electrode pad is improperly positioned or oriented on the torso of the victim, the presence of a multiplicity of electrodes gives the MP some latitude in correcting the error, without having to ask the enabler to remove and reposition the pad. For example, if the pad were rotated 90 degrees, such that electrode 230 (α) was positioned at the left (instead of right) upper torso, and electrode 234 (γ) was positioned at the right upper torso; the MP could apply energy between electrodes 234 (γ) and 232 (β), accomplishing what a standard α-δ application would, had the pad been properly oriented.

[0606] In the event that one or more electrodes is making poor contact with the patient, the MP can identify the poorly contacting electrode(s) and can either work around it or ask the enabler to correct the condition. Circuitry within the PU performs impedance measurements between certain electrode combinations to identify poorly contacting electrode(s). For each measurement, one electrode is electrically isolated, and the other four electrodes are electrically common. For example, the MP would know that the δ electrode is making poor contact if the impedance measurement of δ vs. electrically common α/β/γ/ε is high, while the impedance value of each other combination of one electrode against the other four, e.g. α vs. β/γ/δ/ε is low. Using such an approach, a low impedance measurement implies that the electrically isolated electrode (and at least one other electrode) is making good contact. A high impedance reading implies that either the electrically isolated electrode (and/or all of the electrically common electrodes) is making poor contact. Other impedance measuring algorithms can also identify poorly contacting electrodes. The only distinction that cannot be made by such an approach is the correct identification of a single electrode making good contact, when all of the remaining electrodes are making poor contact.

[0607] The medical professional may work around a poorly contacting electrode if he feels that a properly contacting adjacent electrode will make a reasonable substitute. For example, if the δ electrode is found to be making poor contact, the MP may elect to defibrillate using the α-ε pair, instead of the standard α-δ pair. Alternatively, the MP may ask the enabler to apply pressure over the surface of the δ electrode, perhaps using a circular motion, in order to achieve better δ electrode contact.

[0608] Combinations of two or more electrodes may also be used to apply a lower voltage energy to the victim's torso for pacing the heart. The medical professional would select the choice of electrodes in the same way that he selects the defibrillating electrodes. The choice of pacing electrodes need not be the same as the choice of defibrillating electrodes.

[0609] Table 3 shows how combinations of two or more electrodes may be used to record seven of the twelve standard electrocardiogram leads.

[0610]

TABLE 3
ECG Recording Configuration on Five Electrode Pad
	Lead	Electrode #1	Electrode #2
	I	α	β
	II	α	δ
	III	β	γ
	aVR	α	β + γ
	aVL	β	α + γ
	aVF	γ	α + β
	V3/V4	δ	α + β + γ
	V6	ε	α + β + γ

An eighth configuration, listed in the table as V3/V4 records a composite of the standard lead V3 and lead V4, because of the large size of the δ electrode. Furthermore, the medical professional may elect to record between any combination of electrodes, giving him, in principle, a total of 90 recording options.

[0611] Different numbers, shapes and locations of large electrodes could accomplish the tasks of defibrillation, pacing, ECG monitoring and monitoring of appropriate pad contact.

[0612] Element 204B in FIG. 5B is a modified version of the standard electrode pad 204A. In addition to the five defibrillating electrodes, it contains multiple smaller electrodes 240 (F), 242 (G), 244 (H), 246 (J), 248 (K), 250 (L) and 252 (M). Table 4 shows how combinations of these electrodes could be used to record 10 of the 12 leads of a standard electrocardiogram.

[0613]

TABLE 4
ECG Recording Configuration on Five Electrode Pad
with Seven Sensing Electrodes
	Lead	Electrode #1	Electrode #2
	I	F	G
	II	F	K
	III	G	J
	aVR	F	G + J
	aVL	G	F + J
	aVF	J	F + G
	V1	H	F + G + J
	V3/V4	δ	F + G + J
	V5	K	F + G + J
	V6	ε	F + G + J

Electrode 250 (L), though not situated at one of the standard electrocardiogram lead locations, may nevertheless be of value to the medical professional. The non-victim side of the pad is shown in FIG. 5B. The conductive surface of each of the ECG electrodes faces the opposite or victim side of the pad. A wire extends from each of electrodes 240-252. These wires coalesce to form cable 213, which also contains the five wires extending from the five defibrillating electrodes.

[0614] Impedance measurements involving combinations of the seven small electrodes may be utilized to identify poorly contacting electrodes, using an algorithm similar to that described for the large electrodes. Alternatively, an algorithm involving impedance measurements between combinations of large and small electrodes could be utilized. The only advantage of this latter algorithm is that in cases where only one large and only one small electrode are making proper contact, it could identify which are the properly contacting ones. The algorithm which uses only the five large electrodes, and the algorithm which uses only the seven small ones would fail to identify the properly contacting ones, in circumstances in which only one large and one small electrode are making proper contact.

[0615] An improperly contacting small electrode may indicate that part of an adjacent large electrode is making poor contact. This would be useful information, since partial non-contact of a large electrode would be more difficult to diagnose from impedance measurements and since partial non-contact could reduce the chance of defibrillation success. If, for example, all impedance measurements are low except that between electrode L and the composite of F/G/H/J/K/M, it would imply that the area of poor pad contact might extend beyond small electrode L to large electrode ε. If electrode ε was going to be used for defibrillation, the MP would then ask the enabler to apply pressure over electrodes L and ε, in order to establish better contact between these electrodes and the skin surface.

[0616] Different numbers, shapes and locations of small and/or large electrodes could accomplish the tasks of defibrillation, pacing, ECG monitoring and monitoring of appropriate pad contact.

[0617] Element 206 in FIG. 5C is a modified version of the electrode pad 204B. The lower perimeter, i.e. the perimeter adjacent to electrodes J, I, H, δ and K has been modified to curve upwards to exclude a region overlying the breasts of a female victim. The purpose of the modification is to assure better electrode contact for female victims. The pad is shaped so that at least some breast tissue would lie caudal to the pad, i.e. between the pad and the victim's feet. The breast tissue would thereby not prevent the γ and the δ pads from making proper contact. Pad 206 contains an elliptically shaped β electrode 254, which allows for rostral displacement of the δ electrode, i.e. towards the victim's head, to accommodate breast tissue. The γ electrode 256 is also elliptical in shape, to allow some of the tissue of a female victim's right breast to lie outside of the perimeter of the pad. The ε electrode 259 is similar in shape and position to its counterpart, element 239 in the unmodified version of this pad shown in FIG. 5B.

[0618] In all other aspects the properties and operation of pad 206 are similar to pad 204B.

[0619] Modifications of pad 206 are possible including modification in the shape of any electrode, modifications in which the β and γ electrodes are omitted, modifications in which the long axis of either of the β or γ electrodes is not horizontally oriented, and modifications in which the center of the δ electrode is displaced in either the rostral, caudal, right or left directions. Modifications are also possible in which the size of the α electrode 253 and the δ electrode 258 are smaller than their counterparts in non-concave electrode pad. Modifications are also possible in which the shape of the caudal surface, though concave, differs from that shown in FIG. 5C.

[0620] Other modifications of pad 206 are possible in which different numbers and locations of small and/or large electrodes could accomplish the tasks of defibrillation, pacing, ECG monitoring and monitoring of appropriate pad contact.

[0621] Modifications of pad 206 are possible which do not contain the seven small ECG electrodes In this case, its operation would be similar to pad 204A.

[0622] FIG. 5D shows a view of pad 204B from the side opposite that shown in FIG. 5B. A portion of the protective backing 260 has been peeled off and partially folded. Removing the backing, a procedure performed by the enabler under the direction of the medical professional, exposes the conductive surface of the electrodes as well as an adhesive surface 262. The adhesive surface holds the pad and its electrodes onto the victim's chest, after the pad has been initially placed there by the enabler.

[0623] FIG. 5E shows an edge view of pad 204B, with a view toward the edge which is to be applied to the victim's right. Electrodes 240, 231, 244, 235 and 246, are seen in profile. The electrodes protrude from a non-conductive semi-rigid supporting material 264. A conductive strip 266 is attached to backing 260, and extends from electrode 231 to 244. Conductive strip 266 maintains a low resistance path between electrodes 231 and 244 while the backing is in place. The MP can determine when the enabler has removed the backing, by observing a sudden rise in the resistance of this path. Strip 266 can extend between any two adjacent electrodes.

[0624] In an alternative embodiment, the strip would touch each of two small conductive areas adhering to supporting material 264, which are not ECG electrodes, but which are conductive surfaces dedicated exclusively to allowing the assessment of contact between the backing and the pad. This approach avoids the placement of conductive additional conductive material in contact with the ECG electrode gel. One wire would extend from each of these conductive surfaces to join cable 213, FIG. 5B.

[0625] In another alternative embodiment, a conductive strip is attached to one point on the surface of supporting material 264, runs along the surface of backing material 266, and, at its other end, is attached to another point on the surface of supporting material 264. Each of the two attachment points on 264 is electrically in contact with a wire which goes on to form part of cable 213. When the enabler pulls off the backing material, the conductive strip is broken, terminating electrical continuity between the wires at the two ends of the strip.

[0626] Edge and back views of pads 204A and 206 show features analogous to those seen in FIG. 5E, showing the side view of pad 204B.

3.3 Matrix Electrode Pad

[0627] FIG. 5F shows another type of multi-electrode pad 208, hereinafter referred to as a matrix electrode pad. One group of electrodes is situated to contact the upper right side of the victim's chest. Another group of electrodes is situated to contact the left side of the victim's chest, beneath the breast. Additional electrodes lie on a strip which extends diagonally between the two aforementioned groups of electrodes.

[0628] The large number of closely spaced electrodes in the upper right and lower left groups allows the MP to “construct” composite defibrillating and pacing electrodes of desired shape and location by rendering each of a number of adjacent small electrodes electrically common. The electrodes are made electrically common within the portable unit, following the commands of the medical professional.

[0629] In the embodiment shown in FIG. 5F, thirty electrodes, 268 are each designated by a unique column label (using letters A through K) and row label (using numerals 1 through 3). Thus, the electrode which, on the victim, is most rightward and most rostral is designated as A1, while the electrode which is most leftward and caudal is designated as K3. Actual row and column labels may be printed on the non-victim side of the pad. Two additional electrodes, 270 and 272 are situated on the diagonal strip which connects the right and left sections of the pad. They are designated V₁ and V₂, labels which are consistent with 12 lead ECG designations.

[0630] When using the pad to defibrillate or pace a victim, the medical professional 301 would construct a composite electrode by commanding the portable unit 104 to make a group of electrodes electrically common. For example, the nine electrodes A1-A3, B1-B3 and C1-C3 form a three by three array which could serve as the right chest electrode, analogous to the a electrode 230 on the five electrode pad 204A, FIG. 5A.

[0631] If instead of selecting the electrodes in columns A, B and C, the MP selects the nine electrodes in columns B, C and D, he has effectively “moved” or shifted the location of the right chest electrode toward the midline of the chest. If he wishes to use a larger right chest electrode, he could select all twelve of the electrodes in columns A, B, C and D. If he wishes to use a smaller right chest electrode he could select a two by two array, e.g. A1, A2, B1 and B2; a two by three array, e.g. A1, A2, A3, B1, B2 and B3; or an irregularly shaped array, e.g. A1, A2, A3, B1 and B2. He could select a single electrode, or he could select a non-contiguous group of electrodes. Thus any combination of the twelve right sided electrodes could form the right chest electrode.

[0632] The left chest electrode is selected in a manner similar to that for the right chest electrode. For example, the nine electrodes in columns G, H and J would be a typical choice. If the MP wished to “move” or shift the left chest electrode further leftwards, he could select the nine electrodes in columns H, J and K. If the MP desired a more rightwards location, the electrodes in columns F, G and H could be selected. As is the case with the right chest electrode combination, any combination of left sided electrode(s) could constitute the composite left electrode.

[0633] Electrocardiogram recording is accomplished by utilizing two or more of the thirty two electrodes, as described in Table 5.

[0634]

TABLE 5
ECG Recording Configuration on Thirty Two Electrode Pad
	Lead	Electrode #1	Electrode #2
	I-like	A3	K1
	II	D1	E3
	V1	V1	A1 + A3 + C1 + E3 + G3 + J3
	V2	V2	A1 + A3 + C1 + E3 + G3 + J3
	V3	E1	A1 + A3 + C1 + E3 + G3 + J3
	V4	F1	A1 + A3 + C1 + E3 + G3 + J3
	V5	H1	A1 + A3 + C1 + E3 + G3 + J3
	V6	K1	A1 + A3 + C1 + E3 + G3 + J3

Because of this pad's diagonal orientation, certain modifications in recording technique are required. The absence of electrodes in the vicinity of the left arm results in inability to display lead III and the three augmented leads. Lead I is recorded from the pair of electrodes which are closest to horizontal on the pad. However, the geometry of the pad may result in inability to achieve a perfectly horizontal orientation; hence Table 4 refers to this lead as “I-like.” Similarly, the ordinarily horizontal relationship of leads V₁ and V₂ might be modified to accommodate the diagonal region of the pad. The electric potential at the six V leads, ordinarily subtracted from that of a composite of right arm, left arm and leg, is in this case subtracted from a modified composite consisting of electrodes A1, A3, C1, E3, G3 and J3. Other electrode combinations than those listed in Table 5 could be used, if, at the MP's discretion, the medical situation called for such an analysis.

[0635] The electrode combination used to defibrillate a victim may be different than the electrode combination used for pacing, which in turn may be different from the combinations used for ECG recording.

[0636] As described above in connection with the pads containing five defibrillating/pacing electrodes (FIGS. 5A and 5B), in the event that one or more electrodes in the matrix pad 208 is making poor contact with the patient, the MP can identify the poorly contacting electrode(s) and can either work around it or ask the enabler to correct the condition. Circuitry within the PU performs impedance measurements between electrode combinations to identify poorly contacting electrode(s). For each measurement, one electrode is electrically isolated, and the other thirty one electrodes are electrically common, in a manner similar to that described for the aforementioned pads. For example, the MP would know that electrode D3 is making poor contact if the impedance measurement of D3 vs. an electrically common composite of the other 31 electrodes, is high, while the impedance value of other combinations of electrodes is low The medical professional may work around a poorly contacting electrode if he feels that a properly contacting adjacent electrode will make a reasonable substitute. Alternatively, the MP may ask the enabler to apply pressure over the surface of the poorly contacting electrode, in order to achieve better electrode contact.

[0637] Different numbers, shapes, sizes and locations of electrodes could accomplish the tasks of defibrillation, pacing, ECG monitoring and monitoring of appropriate pad contact. The shape of the pad and the length of the diagonal region is preferably designed to fit the average size person. The electrodes themselves need not be of uniform size or shape, and the inter-electrode distance need not be uniform.

[0638] The back of the pad is constructed in a manner similar to that shown in FIG. 5E. The conductive strip allowing the monitoring of backing removal extends between any two adjacent electrodes.

3.4 Single Electrode Pads

[0639] Another approach to electrode pads is the placement of two or more single electrode defibrillator/pacing pads, as are known in the art, upon the torso. In the embodiment shown in FIG. 5G, three single electrode pads, 210, are in place on the torso. A greater or lesser number of these single electrode pads may be used. (Four pads shown in FIG. 7B.) These single electrode defibrillator/pacing pads are available in the tool-kit section of the Portable Unit, as described above in connection with FIG. 7B. The pads are distinguished from each other by the presence of a numeral on the non-victim surface of the pad, by color, by shape or by more than one such feature. The medical professional instructs the enabler in the proper location of each electrode as described previously

[0640] A wire, 216, extends from each pad leading to universal connector, type D, 218D.

[0641] Standard operating procedure for defibrillation calls for the passage of an electric current between two pads on the victim's chest, one placed high on the chest to the right of the midline, and one placed on the far left side of the chest, beneath the nipple. Alternate approaches involve a single electrode on the chest surface (generally referred to as anterior) and another electrode on the back (generally referred to as posterior), indicated by dashed lines. FIG. 5G shows the placement of two anterior electrodes (labeled “1” and “2” on the pads) and one posterior electrode (labeled “3” on the pad). The posterior placement is indicated in the figure by dashed lines. By placing more than two electrode pads on the torso, the medical professional has options beyond those available for the two electrode approach. These include: a) the ability to repeat defibrillation using a different combination of electrodes if a first attempt fails; b) the ability to apply defibrillating energy simultaneously between more than two electrodes (For example, in FIG. 5G, energy could be applied between pad 1 and pad 2, and between pad 1 and pad 3, simultaneously. Furthermore, this simultaneous application need not involve the same voltage or waveform between the different pairs of electrodes.); and c) the ability to apply energy to different pairs non-simultaneously.

[0642] The single electrode pads may be used for defibrillation, for pacing and/or for recording the electrocardiogram. Any number, shape and size of electrode pads may be utilized; and they need not be of uniform shape or size. Their location may be anywhere on the body, in accordance with proper medical practice.

4. Sample Cardiac Arrest and System Operation

4.1 Overview of Sample Arrest

[0643] For illustrative purposes, an hypothetical cardiac arrest is discussed. The seven major phases of the events during the hypothetical cardiac arrest are described in Table 6:

[0644]

TABLE 6
Seven Phases of Activity During a Cardiac Arrest
	Phase	Time (m:ss)	Activity
	1	0:00-0:31	Initial enabler action from
			the time he first sees victim
			until button press (activation of
			the PU by the enabler)
	2	0:31-0:50	A series of four “handshakes”
			between the MP and the enabler:
			a) communication,
			b) telemetry
			c) audio, and
			d) informational
	3	0:50-2:19	Transport of PU from pre-arrest
			location to victim's side; setup
			of PU at victim's side; four
			layer handshake between victim
			MP, including diagnosis of
			ventricular fibrillation
	4	2:19-3:18	MP treats victim:
			a) first shock
			b) second shock
			c) first pacing
			d) second pacing;
			Treatment causes normalization
			Of heart rhythm
	5	3:18-7:25	CPR, if necessary; victim identification;
			victim data retrieval;
			tracking and waiting for the
			emergency medical team (EMT)
	6	7:25-7:43	A series of four handshakes
			between the MP and the EMT
	7	7:43-variable	MP transfers control of PU to
			EMT; MP advises EMT; MP guides
			enabler in replacement of PU

4.1.1 Phase One: Initial Enabler Action

[0645] The start time, the moment when the enabler 100 first observes the Victim 102, a person who has suffered a cardiac arrest due to ventricular fibrillation, is arbitrarily designated with a time of 0:00. This marks the start of phase one. Nearly all of phase one, which ends when enabler presses the emergency button 106, is the time for the enabler to move from the victim to the portable unit 104.

4.1.2 Phase Two: Handshakes Linking Enabler and MP

[0646] Phase two involves a consecutive series of four handshakes, each one confirming a progressively broader link between the enabler and the medical professional.

4.1.2.1 Role Played By Handshakes; Relationship Between Handshakes and Backups; Relationship Between Handshakes and Links

[0647] The handshakes play an important role in the operation of the system. Since decision making, when performed by the MP, occurs in a location separated from the emergency scene, it is essential that the MP know at all times if his link with the PU is robust. And it is vital that if the MP believes that his link with the PU is not robust, he can take corrective action by: a) directing the PU, the SU or CS to remedy or restore the link; and/or b) directing the PU to switch its guidance from MP-based, to an onboard guidance system, the AED/P (by directing the PU to enter Master Control State 2). It is equally vital that the PU can, at all times evaluate the ongoing link with the MP; and that the PU can, if it recognizes that the link with the MP is not robust, take corrective action by: a) attempting PU-based or SU-based maneuvers to remedy or restore the link; and/or b) switch its guidance from MP-based, to an onboard guidance system, the AED/P (by itself entering Master Control State 2, without the necessity of the MP for this transition). Accordingly, preferred embodiments of this invention provide means for implementing one or more layers of “handshake” (HS). And preferred embodiments of this invention provide means for implementing the aforementioned corrective actions, with one or more levels of backup, in the event of handshake failure.

[0648] In a preferred embodiment of the invention, each handshake after the first one builds on the previous handshake, by either expanding the route over which information exchange is confirmed, or by adding a more complex form of information exchange. The four handshakes of this embodiment may therefore be conceptualized as being layered, each on top of the previous one. The execution of all four handshakes confirms the integrity of a link (see Appendix 2). The four handshakes linking the EN and the MP are summarized in table 7, below.

[0649]

TABLE 7
Four Layers of Handshake Linking Enabler and MP
Layer	Handshake		Backup	Backup	Backup
#	Type	Between	#1	#2	#3
1	Communication	PU & CS	Δ route	Δ mode	MC = 2
2	Data/Commands	PU & CS	Δ	Δ HS	MC = 2
			coding
3	Audio
3A	MP to EN	EN & MP	Headset	Voice Pr	Text Pr
3B	EN to MP	EN & MP	Headset	Keyboard	SpeechRec
4	Informational	EN & MP	Interp'r	FoLanRec	Video CAM

[0650] Embodiments of the invention with a greater or lesser number of handshakes are possible. Embodiments of the invention in which two or more of the aforementioned handshakes are merged are also possible. Embodiments of the invention in which one of the aforementioned layers is sub-divided into multiple layers are possible. Embodiments of the invention in which some or all of the handshakes are not layered, each on top of the previous one, are possible. Embodiments of the invention in which other links (e.g. the Victim-MP link, or the EMT-MP link) have a different number of handshakes or a different handshake format are also possible.

4.1.2.2 Backup Systems for a Failed Handshake

[0651] For each HS, three levels of backup are listed. Embodiments of the invention with a larger or smaller number of backups are possible. Embodiments of the invention are possible which use the same backups listed in Table 7, but utilize them in a different order. Embodiments of the invention with different backup systems are possible.

[0652] Referring to Table 7, for the first two layers of HS, backup #1 and backup #2 are maneuvers which attempt to remedy or restore a less than adequate or interrupted handshake. The third level of backup for the layer #1 and layer #2 handshakes, PU self-programming to Master Control State 2, transfers control of the PU to the AED/P 128, the automatic circuitry which lets the PU function without a link to the central station. Another group of backup options for these two layers, not listed in the table, includes the substitution of a redundant hardware unit for a failed one (by electronic means), once the failure has been located. Yet another option is the manipulation of antenna size, orientation, location, number or shape. Hardware substitution and antenna manipulation may involve the PU, the SU and/or the central station. Backup systems for failed handshakes are discussed in detail, below.

[0653] The AED/P is not likely to be necessary for backing up the third and fourth layers of HS (see below). There are a variety of communications enhancing features (see Table 7 and the text below) which perform the backup functions for layers #3 and #4 of the enabler-MP link.

4.1.2.3 Four Handshakes which Link the Enabler and the MP

4.1.2.3.1 The Communication Handshake

[0654] When the enabler presses the emergency button, the first of the handshakes, a communication handshake, is established between the portable unit and the central station. This handshake is described in detail below in connection with FIG. 12. It continuously lets the PU know that the CS is receiving PU signals and responding properly, while simultaneously letting the CS know that the PU is receiving CS signals and responding properly.

[0655] The handshake involves the transmission of signals over a route that may include, in succession:

[0656] a) the PU microprocessor (which first receives the “button press” signal);

[0657] b) the PU encoder;

[0658] c) the PU transmitter;

[0659] d) the CS receiver;

[0660] e) the CS decoder;

[0661] f) the CS microprocessor

[0662] g) the CS encoder;

[0663] h) the CS transmitter;

[0664] i) the PU receiver; and

[0665] j) the PU decoder.

[0666] The PU decoder then sends a signal to the PU microprocessor, completes the first cycle around this loop. Activation of the PU microprocessor also may thus be considered to mark the first step of the second cycle of what is a continuous set of cycles for the entire duration of the handshake. Any time a microprocessor fails to receive the appropriate signal, it initiates the transmission of alternate signals to reflect its altered input (see below and Table 16). If the PU microprocessor receives signals indicating a handshake failure, it may initiate actions which activate one the backup systems listed in Table 7. If the handshake is unsuccessful, despite multiple attempts using multiple communication routes and modalities, the microprocessor will cause the PU to switch to Master Control State 2, and thereby: a) hand control of defibrillation and pacing over to the automatic external defibrillator/pacer (AED/P) control logic; and b) enable lock release of the PU from the SU (such that MP “approval” of the release is no longer necessary).

[0667] Embodiments of the invention are possible in which the communications handshake involves either a greater or a smaller number of components than the ten listed above as (a) through (j). Embodiments of the invention are possible in which there is only a one-way handshake, e.g. by having the PU receive a continuously transmitted CS signal, and by having the PU microprocessor react to the absence of such a signal by causing backup measures to be instituted.

[0668] When the SU is part of an attempted PU-CS link, the ten item list ((a) through (j) above) is modified to allow for a PU-SU communication handshake and a SU-CS communication handshake (see Sections 4.1.2.4.1, 4.1.2.4.5 and Table 16) Such handshakes would test the SU transmitters and receivers and the SU microprocessor.

4.1.2.3.2 The Data/Commands Handshake

[0669] Once the communication handshake is established, a data and command handshake follows. The data/commands handshake cannot occur unless the communication handshake is running continuously in the background. This second layer handshake lets the MP know: a) that data from the PU can be transmitted from the PU and received by the CS; and b) that commands can be transmitted from the CS, and can be received and executed by the PU.

[0670] The handshake involves the transmission of signals over a route that includes, in succession:

[0671] a) the CS processing input;

[0672] b) the CS encoder;

[0673] c) the CS communications output;

[0674] d) the PU communications input;

[0675] e) the PU decoder

[0676] f) the PU processing output

[0677] g) the PU processing input;

[0678] h) the PU encoder;

[0679] i) the PU communications output;

[0680] j) the CS communications input;

[0681] k) the CS decoder;

[0682] l) the CS processing output;

[0683] The CS and the PU microprocessors may be involved at multiple points along this sequence (see ahead). This handshake may be initiated by an audio signal or sound at the CS. Alternatively it may be initiated by a non-audio command at the CS such as a signal to the PU to send a test ECG. The aforementioned involve two-way handshakes. Alternative methods of handshaking could involve one-way handshakes which may include continuously or intermittently emitted test signals from either the PU or the CS end.

[0684] This data/commands handshake traverses a wider loop than does the communication handshake. A completed data/commands handshake confirms the proper functioning of: a) all of the components included in the communication handshake; b) the CS processing (which includes audio and non audio) input and output components, and the PU processing input and output components; and c) other components which may be involved in test commands and test signals.

[0685] The data/commands handshake may be repeated to confirm the proper execution of each of multiple test commands, or the proper transmission of each of multiple test signals. Alternatively these commands and signals may traverse the system simultaneously. The data/commands handshake may be repeated continuously, intermittently or performed just once during a particular medical emergency (see Section 5.).

[0686] Embodiments of the invention are possible in which the data/commands handshake involves either a greater or a smaller number of components than those referred to above. Embodiments of the invention are possible in which there are one or more different one-way and/or one or more different two-way data/commands handshakes.

[0687] When the SU is part of an attempted PU-CS link, the routine is modified to allow for a PU-SU data/commands handshake and a SU-CS data/commands handshake (see Sections 4.1.2.4.1, 4.1.2.4.5 and Table 16). Such handshakes would further evaluate the SU transmitters and receivers and the SU microprocessor.

[0688] If the layer two handshake is unsuccessful, despite the first two backup approaches (listed in Table 7 and discussed below), then PU entry into Master Control State 2, with resultant enabling of AED/P logic and lock release, is the third level backup approach, as was the case with an unsuccessful communication handshake. After the layer two handshake is complete, the successful transmission and execution of commands is documented by a series of confirmation signals described below; Unsuccessful transmission or execution of individual commands is documented by a series of error signals described below.

[0689] Both the communication and the data handshakes may be established very quickly, i.e. within a time interval on the order of one second or less.

4.1.2.3.3 The Audio Handshake

[0690] After establishment of the data and command handshake, the ability to exchange audio is established during the third layer of handshake. The MP must determine that he can hear the enabler clearly and that the enabler can hear him clearly. Most of the time, any difficulty in this area will be easily remedied (by the MP or by the system) by adjusting an amplifier gain control, or by adjusting another signal conditioning parameter at either the PU or the CS end.

[0691] The audio handshake traverses a wider loop than does the data/commands handshake. This handshake involves the proper passage of information among: a) the twelve data/commands items listed as (a) through (1) in Section 4.1.2.3.2, above; and b) the enabler and the medical professional. Their ability to hear each other involves: a) the proper functioning of the aforementioned twelve items; b) the enabler's ability to adequately hear the audio output of either the PU speakers 146, or the PU handset 150; and c) the MP's ability to properly hear the voice of the enabler, picked up by either PU microphone 148 or PU handset 150. (It is assumed that the speakers, microphones, handsets and/or headsets at the central station can be reliably used and optimized by the MP.)

[0692] When the SU is part of the PU-CS link, a suboptimal audio response may be remedied (by the MP or by the system) by the adjustment of a SU amplifier gain control, or by the adjustment of another signal conditioning parameter among the SU receivers and transmitters, in addition to such adjustments at either the PU or the CS end.

[0693] The backups for this third layer are devices or techniques intended to support a marginally functioning audio system. They include:

[0694] a) EN using PU handset 150 or headset 168;

[0695] b) MP triggering of voice prompts (Voice Pr) which have been pre-recorded and stored in the PU;

[0696] c) MP sending text messages (Text Pr) which appear on one of the PU screens 156;

[0697] d) EN using a virtual keyboard displayed on one of the touch sensitive screens, 156, of the PU; and

[0698] e) MP using a speech recognition program (SpeechRec) within the PU.

[0699] In the event of the enabler not hearing the MP properly, techniques (a), (b) and (c), above, would be used. In the event of MP not hearing the enabler properly, techniques (a), (d) and (e), above, would be used. The detailed algorithm for this is discussed below.

[0700] There is little or no need for AED/P backup for the third layer of handshake. The reason is as follows. With a successful second layer of HS, it has been established that data can flow from PU to CS, and commands may be transmitted to and executed by the PU. If EN can not hear MP directly, then either a) voice or text prompts are recognized by the EN, in which case the MP can proceed to deal with the emergency, in full control of the PU, and able to communicate indirectly with the enabler, or b) voice or text prompts are not recognized by the enabler, in which case an AED would not be likely to function either.

4.1.2.3.4 The Informational Handshake

[0701] The fourth layer of handshake is an informational one. Nine seconds are slotted, starting at 0:41 for the MP to request and receive a description of the medical emergency. During and immediately following the description, the MP decides if the event being described is one in which the PU can be used to help the victim. Backup systems include an interpreter (Interp'r) or a foreign language recognition program (FoLanRec) to deal with a foreign language speaking enabler, and a video camera (Video CAM) to help distinguish a bona fide enabler from a potential prankster. Since this fourth layer of handshake establishes the appropriateness of the medical emergency and of the enabler, AED/P backup is not appropriate for this layer.

[0702] This handshake involves a more complex form of information exchange than that of the audio handshake. Since the informational handshake deals with cognitive issues (viz. the victim diagnosis) it does not involve any additional communication or audio equipment.

4.1.2.4 Role of the Stationary Unit in the Handshake Protocol

[0703] The discussion up to now has not addressed the distinction between a “direct PU-CS link” (i.e. a link between the PU and the CS in which information does not pass through the SU), and an “indirect PU-CS link” (in which the PU-CS link is the composite of a PU-SU segment [wherein information passes between the PU and the SU] and a SU-CS segment [wherein information passes between the SU and the CS]). Either a direct PU-CS link or an indirect PU-CS link must be established. This distinction in routing will now be addressed.

4.1.2.4.1 Single Direct Link Between PU and CS as the Default Routing Approach; Stationary Unit Functions as a Backup

[0704] Conceptually, the simplest approach to a PU-CS link is one in which button press results in the attempted establishment of a direct PU-CS communication link. With such a link, information is sent from the PU to the CS without passing through the SU, and information and commands are sent from the CS to the PU without passing through the SU; The communication in this approach is “wireless.”

[0705] “Wireless,” hereinabove and hereinbelow, refers to communications without a material connection between the two communicating units; such as communication methods employing radio frequency or infrared signal carriers. “Wire,” hereinabove and hereinbelow, refers to communications with a material connection between the two communicating units; such as copper, other metal or optical fiber connections. A wireless connection may include multiple segments, some of which use wire.

[0706] Table 8 and the discussion which follows in this Section and in Section 4.1.2.4.2 address the backup approaches available in the event of a failure in any segment of the PU-CS link, when there is a SU available or involved. “Segment” is hereinabove and hereinbelow defined as a spatially distinct portion of a link, such that the composite effect of all of the segments constitutes the effect of the entire link. Thus the PU-SU segment plus the SU-CS segment constitute the PU-CS (or PU-SU-CS) link. The second through fifth columns of the table refer to each possible segment or link between the PU and the CS. Within Section 4.1.2.4, the term “connection” refers to the physical aspect of a segment, and is used nearly synonymously with “segment.” In the table, “PU-SU wire” refers to the connection between the PU and the SU via connectors 188 and 190; “PU-SU Wireless” refers to a wireless connection between the PU and the SU. In the analysis which follows in Sections 4.1.2.4.1 through 4.1.2.4.4, a link or segment is assumed to be established when the first two layers of handshake, i.e. communications (see Section 4.1.2.3.1) and data/commands (see Section 4.1.2.3.2) are established. This is further discussed in Section 4.1.2.4.5, below.

[0707]

TABLE 8
PU-CS Routing Analysis and Backup When SU is Available
State	PU-SU	PU-SU	SU-		Backup	Backup	Backup
#	Wire	Wireless	CS	PU-CS	#1	#2	#3
1	Any	Any	Any	+	Communication Intact
2	Any	+	+	−	Communication Intact
3	+	−	+	−	PU-176	PU-176	MC = 2
					to SU	to CS
4	−	−	+	−	MC = 2	PU-176
						to CS
5	Any	Any	−	−	MC = 2	PU-176
						to CS
Key
+ = communication intact between indicated units
− = communication not intact between indicated units
Any = + or −, i.e. communication may or may not be intact between indicated units
PU-176 to CS = enabler uses PU wire/jack 176 to connect PU to Telco, i.e. the public telephone network
PU-176 to SU = enabler uses PU wire/jack 176 to connect PU to SU
MC = 2 = Master Control State 2

[0708] In this format (i.e. primary attempt is a direct PU-CS link), only if a wireless link between the PU and the CS could not be established (States #2-#5 in Table 8), would the stationary unit become a unit of the communication chain. In such a situation the backup would involve trying to establish an indirect PU-CS link (i.e. via the SU) The sequence of events could be:

[0709] a) button press;

[0710] b) attempt to establish a direct PU-CS link fails;

[0711] c) the PU, over its connection to the SU via connectors 188 and 190, causes the SU to attempt to establish a connection with the CS;

[0712] d) the SU establishes a connection with the CS; the PU-CS link is then complete since PU is already connected to SU via connectors 188 and 190; the enabler and the MP can now communicate; and

[0713] e) the PU then attempts to establish a wireless connection with the SU.

[0714] Once step (d) is completed, the exchange of vital information between the enabler and the MP can begin (via the wire connection between the PU and the SU), while the system attempts to establish a wireless connection between the PU and the SU. If the attempt (step (e), above) is successful, a proper wireless PU-CS link will have been established, and the PU is ready for detachment from the SU, if the MP decides that the detachment is necessary (based on the enabler's description of the medical emergency).

[0715] The attempted two-segment link between PU and CS can only succeed if both segments, the PU-SU segment, and the SU-CS segment can be established. Section 4.1.2.4.1.1 refers to the situation when: a) both segments can be established; but b) one (but not both) of the PU-SU forms of connection (wire and wireless) can not be established. Section 4.1.2.4.1.2 refers to the situation when one or both of the PU-SU segment and the SU-CS segment can not be established.

4.1.2.4.1.1 Direct PU-CS Link Can Not Be Established; Failure of One But Not Both Possible PU-SU Connections; Successful SU-CS Connection

[0716] The PU-SU segment can be initially established with either a wire or wireless PU-SU connection.

[0717] If the direct connection between the PU and the SU via connectors 188 and 190 is not intact, the PU may attempt to contact the SU via a wireless route. If the PU-SU wireless route is established, and if it is followed by the establishment of a SU-CS connection (State #2, Table 8), a proper PU-CS link will have been established. State #5 (see Table 8), in which the PU-SU wireless route is established but the SU-CS connection can not be established is discussed below in Section 4.1.2.4.1.2

[0718] If a wireless PU-SU connection can not be established, but the wire connection via connectors 188 and 190 is intact, and a SU-CS connection has been established, (State #3, Table 8), the enabler and the MP can communicate only if the PU remains attached to the SU. In this situation, the enabler is advised by the MP of a number of options including:

[0719] a) the option to plug the telephone wire/male jack 176 (from the PU tool-kit) into the female telephone jack 155 of the SU, and thereby to operate the PU with a wire connection to the SU;

[0720] b) the option to use both the wire/jack 176 and an extension wire (located within the PU tool-kit) in tandem, if the wire/jack 176 is not likely to be of sufficient length to reach from the SU to the location where the PU must be placed in proximity to the victim;

[0721] c) the option to transport the PU to the victim (if certain victim-related criteria have been met):

• • [0722] (i) Prior to removal of the PU form the SU (and thereby terminating enabler-MP audio contact), the MP instructs the enabler about upcoming procedures and about how the enabler may interact with the AED/P; He also instructs the enabler that they may be able to resume their communication once the PU has been moved to a location near the victim, either by wireless means, or by having the enabler then plug wire/jack 176 (with or without extension) into a female jack of the public telephone network.
  • [0723] (ii) After properly instructing the enabler, the MP may then give a command to the PU to enter Master Control State 2.
  • [0724] (iii) Enabler then detaches the PU from the SU and transports it to the victim;
  • [0725] (iv) During transport the PU and the CS will attempt to contact each other; if contact is successful, the enabler-MP interaction proceeds as described hereinabove and hereinbelow;
  • [0726] (v) if contact is unsuccessful through the time that enabler arrives at the victim's side, the enabler has the options of either plugging the telephone wire/jack 176 directly (or via the extension) into the public telephone network, or of continuing to use the PU in its AED/P backup mode. The enabler is reminded of these options and of associated details via voice prompts.

[0727] There a multiple possible variations in the timing of the setup of the wireless version of the PU-SU connection: a) the PU-SU connection could be wireless from the beginning, i.e. from the time of button press; b) the PU-SU connection could initially be via connectors 188 and 190, but attempts to establish a wireless PU-SU connection could proceed before, or at the same time as the attempt to establish the SU-CS connection (rather than first establishing the SU-CS connection, as is the scenario described in Section 4.1.2.4.1). If, using one of these variations, the PU-CS link fails to be established, the backups include: a) attempting to use a wire connection for the PU-CS link; b) attempting to use a wire connection for the PU-SU segment; c) AED/P backup (described below in Section 4.1.2.4.1.2).

4.1.2.4.1.2 Direct PU-CS Link Can Not Be Established; Failure of Both Possible PU-SU Connections and/or Failure of SU-CS Connection

[0728] If the direct PU-CS link has failed, then communication between the enabler and the MP can not occur unless an indirect PU-CS link can be established. The indirect link can not be established if: a) neither a wire nor a wireless connection between the PU and the SU can be established (State #4, Table 8); or b) a SU-CS connection can not be established (State #5, Table 8). In either of these two situations, the system must switch to the AED/P backup. The scenario could be:

[0729] a) The PU switches to Master Control State 2.

[0730] b) The PU then issues voice prompts directing the enabler to remove the PU and transport it to the victim's side, if certain victim-related criteria are met (see below).

[0731] c) The enabler then detaches the PU from the SU and transports it to the victim.

[0732] d) From this point in time onwards, the PU will make periodic attempts to communicate directly with the CS. If such an attempt is successful, then the enabler-MP interaction may take place as is described hereinabove and hereinbelow.

[0733] e) If the PU does not make contact with the CS by the time the PU is placed next to the victim (sensor switches 178 signaling placement of the PU), a voice prompt then tells the enabler that he has two options. The enabler may select option (i), and then go to option (ii) if option (i) is unsuccessful, or may select option (ii) initially:

• • [0734] (i) to extend telephone wire/male jack 176 (with or without the extension) from the PU tool-kit to connect to a female jack of the public telephone network; and after sensing such connection the PU will attempt to establish a link with the CS; if the attempt is successful, then the enabler-MP interaction takes place as described hereinabove and hereinbelow; if the attempt is unsuccessful, the enabler proceeds with option (ii) (which follows hereinbelow);
  • [0735] (ii) to use the PU as an automatic external defibrillator; the PU will then further instruct the enabler via voice prompts.

[0736] It is highly unlikely that a SU-CS connection would not be able to be established, since: a) there are many possible routes including the public telephone network, the internet, private communications networks, or combinations of these; and b) the ability to establish the SU-CS connection would be examined and assured at the time that the SU is initially set up, and at other times when diagnostic checking is performed (see below). It is also highly unlikely that neither form of PU-SU connection would be able to be established, for the same two aforementioned reasons regarding the likelihood of being able to establish a proper SU-CS connection.

4.1.2.4.2 Two Connections: One from PU to SU and One SU to CS as the Default Routing Approach

[0737] In a preferred embodiment of the invention, a portable unit would be wired directly to the SU via connectors 188 of the PU (FIG. 8) and 190 of the SU, and a stationary unit (FIG. 9) would be connected via its telephone wire and male jack 198 directly to the public telephone network. Therefore a PU-SU-CS link, free of any wireless segments, could be initially established. The advantage of this approach (as opposed to the direct PU-CS link) is that the absence of any wireless segment within the system will render the link robust. The disadvantage of this approach is that in order for the system to be usable in conjunction with a victim, another connection must be established when the PU is transported to the side of a victim; Either a wireless PU connection (to either the SU or the CS) must be established; or a wire must be extended from the PU (to either the SU or a female jack of the public telephone system).

[0738] In this PU-SU-CS format, the sequence of events could be:

[0739] a) button press;

[0740] b) the PU, over its connection to the SU via connectors 188 and 190, causes the SU to attempt to establish a connection with the CS;

[0741] c) the SU establishes a connection with the CS; the PU-CS link is then complete since PU is already connected to SU via connectors 188 and 190; the enabler and the MP can now communicate; and

[0742] d) the PU then attempts to establish a wireless connection with the SU.

[0743] The analysis of the backup approaches for the two-segment PU-SU-CS link can be dichotomized by considering: a) the situation in which the two-segment approach is initially successful (Section 4.1.2.4.2.1, below); and b) the situation in which the two-segment approach initially fails (Section 4.1.2.4.2.2, below). The backups ultimately consist of the same approaches as those discussed in Sections 4.1.2.4.1.1 and 4.1.2.4.1.2 above, except that: a) the backups also include an attempt to establish a direct PU-CS link (This link assumed to have failed in the backup approaches discussed in Sections 4.1.2.4.1.1 and 4.1.2.4.1.2.); and b) the order in which the backups are selected may differ from that in the Sections hereinabove.

4.1.2.4.2.1 Two-Segment Default; Initial PU-CS Link Successful

[0744] Once step (c) is successfully completed, the exchange of vital information between the enabler and the MP can begin (via the wire connection between the PU and the SU), while the system attempts to establish a wireless connection between the PU and the SU. If the attempt (step (d), above) is successful, a proper wireless PU-CS link will have been established, and the PU is ready for detachment from the SU, if the MP decides that the detachment is necessary (based on the enabler's description of the medical emergency).

[0745] If the attempt (step (d) above) is unsuccessful, the PU may then attempt to establish a wireless connection directly with the CS. If the latter attempt is successful, a proper wireless PU-CS link will have been established. If the latter attempt is unsuccessful, the situation is the one described by State #3, Table 8; three backup options are listed in the table and described in paragraphs (a), (b) and (c) in Section 4.1.2.4.1.1. These options include extending the PU-SU wire connection (paragraphs (a) and (b), Section 4.1.2.4.1.1), moving the PU to the victim and then attempting either a wire or wireless PU-CS connection (paragraph (c), Section 4.1.2.4.1.1) or using the AED/P function of the PU (paragraph (c), Section 4.1.2.4.1.1).

[0746] An alternate sequence is possible as the follow-up to step (c) (of this Section). Instead of next performing step (d), in which the PU attempts to establish a wireless link with the SU, the PU could instead attempt to establish a wireless link with the CS. If this failed, it could then attempt to establish a wireless link with the SU; and if the latter attempt failed, the three backup options of paragraphs (a), (b) and (c) of Section 4.1.2.4.1.1 would be employed.

[0747] There a multiple possible variations in the timing of the setup of the wireless version of the PU-SU connection: a) the PU-SU connection could be wireless from the beginning, i.e. from the time of button press; b) the PU-SU connection could initially be via connectors 188 and 190, but attempts to establish a wireless PU-SU connection could proceed before, or at the same time as the attempt to establish the SU-CS connection (rather than first establishing the SU-CS connection, as is the scenario described earlier in this Section). If, using one of these variations (in the timing of the setup of the PU-SU wireless connection), the PU-CS link fails to be established, the backups are among those already described including: a) attempting to use a wire connection for the PU-SU segment; b) attempting a direct PU-CS link; and c) using AED/P backup.

4.1.2.4.2.2 Two-Segment Default; Initial PU-CS Link Unsuccessful

[0748] According to the four step scenario described in Section 4.1.2.4.2, button press does not result in the establishment of a two segment PU-CS link, then: a) the PU-SU wire connection (step (b)) will have failed; and/or b) the SU-CS connection (step (c)) will have failed.

[0749] A logical backup option would then be to try to establish a direct PU-CS link. If this failed, an attempt to establish a wireless PU-SU connection would follow. If both of these attempts failed, the backup would be the AED/P function of the PU (paragraph (c), Section 4.1.2.4.1.1).

[0750] Alternatively the order of the aforementioned wireless attempts could be reversed, such that the wireless PU-SU connection is first attempted, and if it fails, the wireless PU-CS connection is attempted. Again, the AED/P function is the backup if both of these fail.

[0751] Failure to establish either a PU-SU connection or a SU-CS connection is highly unlikely for the reasons stated above at the conclusion of Section 4.1.2.4.1.2

4.1.2.4.3 Redundant Links, in which There is Both a Direct PU-CS Link and an Indirect PU-SU-CS Link

[0752] Another approach to the establishment of the PU-CS link is to attempt to simultaneously establish both a direct PU-CS link and an indirect (two segment) PU-SU-CS link. There could be up to three simultaneous initial attempts including: a) a direct PU-CS (wireless) link; b) an indirect PU-SU-CS link, in which the PU-SU segment is a wireless connection; and c) an indirect PU-SU-CS link in which the PU-SU segment is a wire connection.

[0753] As soon as any one of these was established communications between the enabler and the MP could begin. There would then be multiple options:

[0754] a) If the first established link is a direct PU-CS link, a second link might or might not be attempted involving the PU-SU-CS route, with a wireless PU-SU connection. If established, the second link could then be available as an immediate backup, if the PU-CS link is interrupted.

[0755] b) If the first established link is an indirect PU-SU-CS link, in which the PU-SU connection is wireless, a second link might or might not be attempted involving a direct PU-CS link. If established, the second, direct PU-CS link could then be available as an immediate backup, if the indirect PU-SU-CS link is interrupted.

[0756] c) If the first established link is an indirect PU-SU-CS link in which the PU-SU segment is a wire connection, a second route must be established (to allow detachment of the PU from the SU). Approaches in which only one second route is established (i.e. either a wireless PU-SU connection or a wireless PU-CS connection) have been described above in Section 4.1.2.4.2.1. Another alternative is to attempt to establish both wireless connections; one could then serve as the primary route and the other as a backup

[0757] If none of these three routes were viable, the backup would be via the AED/P function of the PU, described above in Section 4.1.2.4.1.2.

[0758] The advantage of establishing multiple simultaneous communication routes is that it renders the system more robust. The disadvantage is a potential cost increase.

[0759] Embodiments of the invention with a larger number of simultaneous routes between the PU and the CS are possible.

4.1.2.4.4 More Elaborate Routes for the PU-CS Link

[0760] Embodiments of the invention in which the routing for the PU-CS link is other than as described above (the direct link and the indirect PU-SU-CS link) are possible. These include:

[0761] a) PU-SU-CS links which use a SU different than the SU to which the PU was attached;

[0762] b) links in which two or more SUs operate in tandem (one of which may or may not be the SU to which the PU was initially attached;

[0763] c) links in which there are two or more PUs operating in tandem (see Section 4.5.7.5.2.2, below);

[0764] d) links in which there are two or more central stations operating in tandem; and

[0765] e) combinations of (a) through (d), above.

4.1.2.4.5 Depth of Handshake Layers

[0766] Since the audio handshake (layer 3, Section 4.1.2.3.3) and the informational handshake (layer 4, Section 4.1.2.3.4) between the enabler and the MP involve actual conversation, neither one can take place until both the PU-SU segment and the SU-CS segment have been established. Therefore, in the discussion in Sections 4.1.2.4.1 through 4.1.2.4.4, it has been assumed that either a PU-SU segment or a SU-CS segment is complete as soon as the first two layers of handshake occur. The third (and then the fourth) layer handshakes (between the enabler and the MP) are attempted after: a) both the PU-SU and the SU-CS segments are established (with completed first and second layer handshakes); and/or b) the PU-CS link is established (with completed first and second layer handshakes).

4.1.3 Phase Three: Transport of PU to Victim; Victim-MP Handshake; PU Setup at Victim's Side

4.1.3.1 PU Release and Transport

[0767] Referring again to Table 6, phase three begins when the MP decides that the PU should be used for a resuscitation effort, and, having so decided, issues a command to release the lock which secures the PU to the SU. Preferred embodiments of the invention have backup lock release mechanisms which may be either mechanical, electrical or both (see Section 2., description of FIGS. 8 and 9).

[0768] During the time that the enabler is transporting the PU to the victim's side, there is frequent reassessment of the quality of the enabler-MP link. If the link either deteriorates in quality or is lost as the PU is being moved, the MP, the system, and/or the enabler may utilize any of the backups listed in Table 7 or Table 8 and discussed in conjunction with these tables. If the MP notes that the quality of the enabler-MP link is deteriorating as the PU is being moved, he may so inform the enabler and may provide specific corrective instructions to the enabler (see tables 7 and 8 and the associated discussion).

[0769] Phase three, like phase one, also includes an interval of variable duration, encompassing the transit time for the enabler carrying the PU to the victim's side. The enabler's speed, while carrying the PU, is assumed to be 1 mile per hour slower than it was when he was walking without the PU, and hence a travel time that is 11 seconds longer than the phase one travel interval is allotted.

4.1.3.2 Handshakes Linking Victim and MP

[0770] After the electrode pad is applied during phase three, an electrical link between the victim and the MP, consisting of a layered sequence of handshakes, establishes: a) that the electrode pad is making appropriate contact with the victim; and b) that the diagnosis is ventricular fibrillation.

4.1.3.2.1 The Four Layer Victim-MP Link

[0771] The victim-MP link is conceptually similar to the link between the enabler and the MP described above. Table 9, below, summarizes the main features of this series of handshakes.

[0772]

TABLE 9
Four Layers of Handshake Linking Victim and MP
Layer	Handshake		Backup	Backup	Backup
#	Type	Between	#1	#2	#3
1	Communication	PU & CS	Δ route	Δ mode	MC = 2
2	Data/Commands	PU & CS	Δ coding	Δ HS	MC = 2
3	Electrical
3A	MP to Vi	VI & MP	pressure	Δ electrode	Δ pad
3B	Vi to MP	VI & MP	p/Δ gain	Δ electrode	Δ pad
4	Informational	VI & MP	Δ gain	Δ ECG lead	Δ pad

The handshakes which constitute layers 1 and 2 will have already been established during the enabler-MP link, before phase three begins. In addition, the ongoing functionality of these two layers is continuously re-evaluated. In layer 3 of the victim-MP link, the handshake is based on: a) the determination that impedance measurements in the circuits that include the pad electrodes and the victim are within the proper range (referred to in the table as “MP to victim”); and b) adequate quality of the electrical signals, if any, recorded from the victim (referred to in the table as “victim to MP”). Layer 4, the informational handshake, consists of the MP reading the electrocardiogram signals and thereby diagnosing the victim's heart rhythm.

[0773] As was the case with the link between enabler and MP: Within the link between the victim and the MP, layer 2 is based on an intact layer 1, layer 3 is based on an intact layer 2, and layer 4 is based on an intact layer 3.

4.1.3.2.2 Backup Systems for Failure in the Victim-MP Link

[0774] The backups for problems within the first two layers of the Victim-MP link are similar to those for the enabler-MP link. The electrical (third layer) handshake, analogous to the audio handshake of the enabler-MP link, has backups intended to address a poor electrode-victim interface.

[0775] If impedance readings are high (third layer handshake; MP to victim), the MP may ask the enabler to temporarily press down over the section of the pad or pads which show a high impedance, hoping to thereby improve electrode-victim contact. If this fails, the MP may be able to work around the problem by using other better functioning electrodes, if they are present in adequate number and location. If neither of these is successful, the MP may ask the enabler to remove the electrode pad, and to reapply it or another pad.

[0776] If the ECG signal is of poor quality (third layer handshake; victim to MP), the MP has all of the options previously mentioned for improving the impedance. The notation of p/Δ gain refers to dual first level MP options of either: a) asking the enabler to apply pressure over the pad, as described above; or b) changing the amplifier gain on the channel(s) corresponding to a low amplitude ECG signal.

[0777] During the informational phase, when the MP must diagnose the rhythm abnormality, the first level of backup involves switching the ECG lead. This is a non-mechanical process which involves looking at different pairs of recording electrodes, hoping to identify a pair with a signal that can lead to the rhythm diagnosis. Besides the backup options of changing gain and changing electrode pad, there are a variety of signal enhancing options that are discussed below in Section 4.3.1.2.

4.1.3.3 MP Commands, Confirmation Signals and Error Signals

[0778] Confirmation signals are first utilized in phase three, and extensively in phase four. Like the handshakes, they are an important feature of an emergency management system in which the expert who is making and enacting decisions (the MP) is physically separated from the device that he is controlling. In a preferred embodiment, confirmation signals tell the MP that the command that he initiated has reached a certain checkpoint along its intended route. Error signals tell the MP that a command failed to reach a certain checkpoint. Other types of error signals inform the MP of faults within the system, or faults at the periphery of the system. System is defined as the hardware and software which comprise the PU or PUs, the CS, and the SU (if any). The periphery of the system is defined as any device or individual (other than the victim) which interfaces with the system. Such devices would include blood pressure and oxygen saturation sensors, and the electrode pads. Faults involving individuals interfacing with the system include improper EMT or MP identification.

[0779] A simplified version of the sequence of events following an MP command, including confirmation signals, is

[0780] a) MP issues command;

[0781] b) CS transmits the command;

[0782] c) PU receives the command;

[0783] d) PU executes the command;

[0784] e) PU transmits a confirmation signal that indicates that the command was executed;

[0785] f) CS receives the transmitted confirmation signal;

[0786] g) CS displays the confirmation signal; and

[0787] h) MP sees the confirmation signal.

[0788] In the aforementioned format, there is a single confirmation signal for each command which indicates its successful execution. In a preferred embodiment of the invention, a more complex system of confirmation signals is used which utilizes multiple confirmation signals for each command. For a given command, each successive confirmation signal confirms the proper progress of the command as it passes each of a number of checkpoints in its traversal of the route from MP to point of execution. Command confirmation may occur:

[0789] a) after the command is encoded, indicating that it was properly formulated and encoded;

[0790] b) after the command is transmitted, indicating that transmission was proper;

[0791] c) after it is received by the PU; and

[0792] d) after it is executed by the PU.

Error signals are made available to the MP to indicate failure of the command to traverse a given point in the system.

[0793] Identification of the location of a fault in the system is based on which particular confirmation signal(s) and which particular error signal(s) are received by the MP. Embodiments in which a greater or a lesser number of confirmation and error signals occur are possible.

[0794] In the event of failure of execution of a command, the MP can exercise various backup options including:

[0795] a) repeating the command;

[0796] b) reassessing the robustness of communication and performing necessary remedial measures (see below);

[0797] c) handing control over to the built in backup system, the AED/P; or

[0798] d) the substitution of a redundant hardware unit for a failed one (by electronic means), once the failure has been located.

[0799] This confirmation system will be described in detail below.

4.1.3.4 Telemetry Signals

[0800] Telemetry signals may be considered to be analogous to confirmation signals. Telemetry signals are sent from PU to CS, indicating a PU-based event that was not initiated directly by the MP. Examples include detachment of the PU from the SU by the enabler, and touchdown of the PU after proper orientation by the enabler. Other telemetry signals may indicate faults within the system, or be part of a periodic system diagnostic evaluation.

4.1.4 Phase Four: Emergency Medical Management of the Cardiac Arrest by the Medical Professional

[0801] The fourth of six phases of the hypothetical cardiac arrest encompasses the treatment, by the MP, of the victim's heart rhythm abnormalities. For illustrative purposes, four treatment steps are shown. In its most simplified form, a cardiac arrest could consist only of one step: a single corrective shock, followed by the emergence of a normal rhythm. In order to more fully illustrate some of the capabilities of a preferred embodiment of the invention, the arrest described herein (in connection with Tables 6 and 10) is a more complex one.

4.1.4.1 Defibrillation and Pacing by the MP

[0802] In the arrest described in Tables 6 and 10, the first shock fails to terminate VF. The MP then alters the shock vector by changing one of the pair of electrode pads through which the defibrillating pulse is applied. The MP then causes the PU to deliver a second shock. The MP notes that the second shock was successful in terminating VF, but that asystole (the absence of any cardiac electrical activity), has ensued post-shock. He treats this by causing the PU to deliver pacing stimuli to the victim's chest, at a rate of 60 beats per minute.

4.1.4.2 Other Actions Directed by the MP to Support Blood Pressure

[0803] Two minutes and forty three seconds into this hypothetical arrest, an acceptable heart rhythm has been restored. The MP must now determine if the restoration of reasonable electrical function to the victim's heart is accompanied by a parallel restoration of mechanical function. The MP must therefore determine if the victim has adequate blood pressure and respiratory function. In order to make this determination, the enabler is brought into play again, briefly. The MP asks the enabler to assist in the application of a non-invasive blood pressure device and a transducer for measuring the victim's blood oxygen status. The MP observes a borderline low blood pressure. He then reduces the pacing rate and observes the emergence of a normal rhythm, and a rise in blood pressure. This completes phase four.

4.1.5 Phase Five: Management Immediately Post Electrical Resuscitation

[0804] During phase five, cardiopulmonary resuscitation is performed, if deemed necessary by the medical professional. The MP obtains victim identification and prior medical information. The MP also communicates with the en-route emergency medical team, and reports their estimated time of arrival to the enabler.

4.1.6 Phase Six: EMT Arrival, Transfer of Control of the PU from MP to EMT

[0805] The onset of phase six is marked by the arrival of the EMT. The MP may, if the EMT is appropriately qualified and identified, hand over control of the PU to the emergency medical team. In the scenario described by the sample arrest in Section 4.2, below, we assume that the EMT is desirous of such transfer.

4.1.6.1 EMT Choices Other Than Assuming Control of the PU Currently Attached to the Victim

[0806] Other EMT choices include:

[0807] a) EMT wishes to assume control over rhythm management using another portable unit (hereinafter referred to as “new PU”) which is an embodiment of the invention, but not the same unit which up until that moment was used on the victim (hereinafter referred to as “old PU”) (The new PU and the old PU may or may not be identical embodiments of the invention.).

[0808] b) EMT wishes to have the MP continue to manage heart rhythm abnormalities, using the old PU, with EMT function then restricted to (i) starting an intravenous line for the victim, (ii) giving intravenous medication if necessary, (iii) performing CPR (cardiopulmonary resuscitation) if necessary and (iv) transporting the victim to the hospital;

[0809] c) the same scenario as (b), except that EMT wishes to do this with the new PU;

[0810] d) EMT wishes to assume control over rhythm management using a defibrillator apparatus which is different than the invention;

4.1.6.2 Handshakes Linking EMT and MP

[0811] The transfer of control of the PU from MP to EMT is based on a series of four handshakes, which are conceptually similar to the four handshakes which establish the enabler-MP link at the start of the emergency. Layers 1 and 2 of the EMT-MP link may be identical to those of the EN-MP link: communication and data/command handshakes, running continuously in the background. Layer 3 is an audio handshake between the MP and the EMT. They both confirm that they can adequately hear each other, with the MP making any appropriate adjustments to facilitate this, as was the case with the enabler-MP handshake. The fourth handshake involves the exchange of information between the MP and the EMT. After the audio link is secure, the MP asks the EMT for either a password (“PWD”) (which may be numeric or one or more words), or seeks other evidence that EMT is represented by an appropriate, competent individual (which may be determined by fingerprint, voice, facial and/or iris recognition, or by direct conversation). EMT identification thus constitutes the informational, fourth layer of the EMT-MP link.

[0812] The four layers which constitute the link between the EMT and the MP, and the backups for these four layers are summarized below, in Table 10:

[0813]

TABLE 10
Four Layers of Handshake Linking EMT and MP
Layer	Handshake		Backup	Backup	Backup
#	Type	Between	#1	#2	#3
1	Communication	PU & CS	Δ route	Δ mode	PWD:
					MC = 3
2	Data/Commands	PU & CS	Δ	Δ HS	PWD:
			coding		MC = 3
3	Audio
3A	MP to EMT	MP &	Headset	Voice Pr	Text Pr
		EMT
3B	EMT to MP	EMT &	Headset	Keyboard	SpeechRec
		MP
4	Informational	EMT &	Interp'r	Voice Re	Video CAM
		MP

4.1.6.2.1 First and Second Layers of EMT-MP HS: Password Which Gives Control of PU to EMT, Rather Than to Giving Control of PU to AED/P

[0814] As discussed in Section 4.1.3.2.1, the handshakes which constitute layers 1 and 2 will have already been established during the enabler-MP link, and the ongoing functionality of these two layers is continuously re-evaluated. As is indicated in Table 10, the first two levels of backup for an EMT-MP handshake failure in layer #1 or #2 are identical to those for the enabler-MP link.

[0815] The third level of backup for an EMT-MP handshake failure in layer #1 or #2 differs from that of the enabler-MP handshake. It involves the use of a password by the EMT. The password, when appropriately supplied, causes the PU to enter Master Control State 3, which enables control of the unit by the EMT. This approach differs from that used in the enabler-MP link, in which the third level of backup for handshake failure in layers #1 and #2 is entry of the PU into Master Control State 2, enabling control of the unit by the AED/P. The rationale for this difference in approach is that if communication (or data/commands exchange) between the PU and the CS fails when the EMT is present, it makes more sense to give control of the PU over to the EMT, rather than giving it over to the AED/P. Accordingly, the EMT is provided with a password which, in the event of failure of PU-CS handshakes at layers #1 or #2, will allow the EMT to cause PU to enter Master Control State 3, giving EMT control of the PU. The password may be supplied to the EMT when the EMT is summoned, or at an earlier time. Alternatively, password acceptance may require matching pre-programmed EMT anatomic features (fingerprint, iris, etc.).

[0816] In a preferred embodiment, as long the handshakes in layers #1 and #2 are intact, password acceptance requires the participation of the MP, and occurs in level four. Only in the event of handshake failure in layers #1 or #2, would the EMT password cause the transfer of control of the PU to the EMT, without the MP causing such transfer. This approach makes the system least likely to have its control usurped by an inappropriate person.

4.1.6.2.2 Third and Fourth Layers of EMT-MP HS

[0817] The third layer of this handshake, is entirely analogous to the third layer of the enabler-MP handshake. The goal is the establishment and confirmation of adequate quality audio in both directions. The backups for the third layer are the same in both cases.

[0818] As indicated above, the informational handshake of level four is the password. Backup systems are intended to enhance EMT identification, in the event that a putative password does not match. The backups include an interpreter, and techniques for recognizing individual characteristics including voice (Voice Re), facial and other anatomic features (via video camera).

4.1.7 Management by the EMT, after Transfer of PU Control to the EMT, by the MP

[0819] The traditional role of the emergency medical team includes all aspects of the management of the victim from the time they arrive at the scene of the emergency, until they arrive in hospital.

4.1.7.1 Transfer of PU Control

[0820] Once the EMT is deemed by the MP to be appropriate, and desirous of assuming control over the PU, the MP may transfer control of the PU to the EMT. Phase seven begins when the MP decides that control of the PU should be transferred to the EMT, and, having so decided, issues a command to effect such transfer. Phase seven ends when both: a) the victim is no longer attached to the PU; and b) when the PU has been returned to the SU (see Section 4.5.7.8).

4.1.7.2 Briefing of EMT by MP

[0821] Following the transfer of control, the MP provides the EMT with information which summarizes the events which occurred prior to the arrival of the EMT, and other data deemed to be important by either the MP or the EMT. Such information would include:

[0822] a) the victim's current status including (i) his rhythm status over the last few minutes (Meanwhile, the victim's real time rhythm status, i.e. the current ECG, would be displayed on one of the PU screens.) and (ii) his current vital signs;

[0823] b) the victim's initial heart rhythm;

[0824] c) the major events that took place during the resuscitation, i.e. defibrillation and pacing, and the results of each therapeutic intervention by the MP;

[0825] d) the victim's blood pressure recordings during the event;

[0826] e) the victim's respiratory status during the event;

[0827] f) the elapsed time since MP involvement with the emergency began;

[0828] g) the elapsed time since the emergency began (if known);

[0829] h) the victim's latest and prior states of responsiveness;

[0830] i) information obtained from enabler's initial description of the victim, i.e. that obtained immediately before MP release of the PU to the enabler;

[0831] j) information about the victim's medical history; including (i) events immediately preceding the current emergency and (ii) events and medical conditions which predate the current situation; and

[0832] k) information about the victim's medications, if any;

[0833] l) information about the victim's medication allergies, if any;

[0834] m) information about victim's next of kin, if known. Items (a) through (f) are stored within the PU memory for the duration of the event. They are also stored within the CS memory, as are items (j) through (m), if known. Items (g), (h) and (i) may be related to the EMT by the MP. All victim and event data, audio and video recordings become a part of the permanent CS record.

[0835] Storage and transmission of victim-related and event-related information is performed in compliance with all local and federal statutes regarding privacy, encryption and restriction of access.

[0836] The duration of the information presentation and the level of detail will depend on: a) the severity of victim's condition at the moment of EMT take-over; and b) the number of EMT personnel. (A larger team means that someone is more likely to be free to obtain the information.)

[0837] The information may be presented in any of the following formats:

[0838] a) enabler narrative by voice communication;

[0839] b) text summary, on one of the PU screens;

[0840] c) ECG summary (the important recordings made during the resuscitation procedure), on one of the PU screens;

[0841] d) text printout (A small printer may be included in the PU.);

[0842] e) ECG printout; and

[0843] f) combinations of (a) through (e).

[0844] In addition to supplying the EMT with patient related information, the MP may, if necessary, provide the EMT with information about the use and operation of the PU.

4.1.7.3 Method of PU Operation by the EMT

[0845] The EMT uses the PU in a similar fashion to the way that the medical professional uses his console at the central station. That is, the PU screens 156: a) display vital information such as the victim's ECG, blood pressure and respiratory status; b) serve as touch sensitive screens with the same screens for defibrillator and pacer control, and for ECG viewing and electrode pad setup as those used by the MP (FIGS. 29 through 40); and c) can display an appropriately truncated version of the Screen Menu (FIG. 43) used in the central station (The truncated Screen Menu does not give the EMT access to screens which would be inappropriate and unnecessary for the EMT, such as the Video Control Screen (FIG. 28). Additional screen capacity may be achieved with screen-in-screen and split screen methodology, as was discussed in Section 2. In a preferred embodiment of the system, the PU may generate instructional prompts, either voice or text, to help guide the EMT regarding PU operation.

4.1.7.4 MP Role During EMT Use of the PU

4.1.7.4.1 Medical and Technical Support by the MP

[0846] In a preferred embodiment of the invention, the MP link with the PU remains intact, even after handoff of PU control to the EMT. Therefore the MP may continue to:

[0847] a) view victim data (ECG and other);

[0848] b) view EMT commands;

[0849] c) speak with the EMT; and

[0850] d) observe the arrest scene.

[0851] Therefore, there are a number of possible formats for the relationship of MP to EMT, during EMT use of the PU. These include:

[0852] a) active involvement by the MP, in an advisory capacity, in medical decision making (i.e. MP makes suggestions about victim management whenever MP feels it is appropriate);

[0853] b) involvement in a medical advisory capacity, only when consulted by the EMT;

[0854] c) active involvement by the MP, in an advisory capacity, in a technical support role (i.e. advising the EMT about PU operation whenever MP feels it is appropriate);

[0855] d) involvement in a technical support role, only when consulted by the MP; and

[0856] e) no MP involvement whatsoever.

[0857] “Active” may refer to any frequency of giving advice, from frequent to infrequent. Which of (a) through (e) is selected may be based on both EMT and MP preference, and may be based on local statutes or protocol. The choice of (a) through (e) may vary during the course of a particular emergency. For example: Although the EMT might be fully capable of medical management of the victim and proper use of the PU, he might fail to notice a sudden change in the victim's heart rhythm. This could occur while the EMT is starting an intravenous line for the victim. The MP, in such a situation, could immediately inform the EMT.

[0858] Medical advice which the MP could provide includes:

[0859] a) helping the EMT make a correct rhythm diagnosis;

[0860] b) helping the EMT select the correct treatment modality (e.g. shock versus giving intravenous medication);

[0861] c) helping the EMT select the correct treatment parameters (e.g. high energy shock versus low energy shock);

[0862] d) advising the EMT as to the adequacy of CPR performance (e.g. by monitoring oxygen saturation);

[0863] e) advising the EMT of a sudden change in the victim's status which the EMT may not have noticed (see example above); and

[0864] f) pharmacologic advice (see below).

[0865] At any time, the EMT may request that the MP resume control of the PU. This may occur if:

[0866] a) additional electrical therapy is necessary (defibrillation or pacing) and the EMT feels that the MP's medical expertise is superior to EMT's

[0867] b) the EMT feels that the MP's technical expertise (regarding operation of the portable unit) is superior to EMT's;

[0868] c) one or more members of the emergency medical team is involved in medical activities such as CPR or intravenous line placement, which do not allow them to pay adequate attention to heart rhythm issues;

[0869] d) one or more members of the emergency medical team is involved in transport activities, which do not allow them to pay adequate attention to heart rhythm issues;

[0870] e) combinations of (a) through (d).

4.1.7.4.2 Pharmacologic Support by the MP

[0871] Once one of the members of the emergency medical team has started an intravenous line for the victim, there is the opportunity to administer a variety of intravenous medications including:

[0872] a) drugs to help regulate the heart rhythm (antiarrhythmic drugs);

[0873] b) drugs to increase the intensity of the heart's mechanical action (inotropic drugs);

[0874] c) drugs which increase the heart rate (chronotropic drugs);

[0875] d) drugs which alter the metabolic status; and

[0876] e) drugs which prevent blood clotting (antithrombotic agents) or promote clot dissolution (thrombolytic agents).

[0877] The EMT opportunity to administer intravenous medication adds another item to the potential MP advisory role. The MP advice may be based on: a) the MP's own expertise; b) rapid access to other experts in pharmacologic matters; and c) rapid access to databases which contain pharmacologic information. The MP pharmacologic advice to the EMT may include:

[0878] a) suggestions or information about choice of drug (if any), and dosage;

[0879] b) suggestions about rate and route of drug administration;

[0880] c) advice about expected drug effect;

[0881] d) advice about potential drug-drug interactions;

[0882] e) reminders about current victim medications (if known) drug allergies (if known).

4.1.8 MP Role After Victim Arrives at the Hospital

[0883] The MP may continue to function in an advisory capacity after the victim reaches a hospital. That is, treating physicians at the hospital which receives the victim may wish to utilize the MP, because of a number of potential of advantages to such an approach including:

[0884] a) the MP's high degree of expertise and experience in the management of heart rhythm abnormalities may exceed that of any of the physicians in the hospital;

[0885] b) the MP's rapid access to other experts;

[0886] c) the MP's rapid access to pharmacologic databases;

[0887] d) the MP's rapid access to the victim's past medical history; and

[0888] e) the fact that the MP has become familiar with the victim and his response to therapy over the course of the current medical event.

[0889] It is furthermore possible that hospital physicians may request that the MP resume control of electrical therapy, for each of the reasons (listed above) that EMT may make such a request.

4.2 Sample Cardiac Arrest: Correspondence Between Events During the Arrest, Flow Diagrams, Screens, Handshakes and Confirmation Signals

[0890] Table 11 shows the sequence of events that constitute the hypothetical cardiac arrest. This table also shows the correspondence between:

[0891] a) events during the arrest;

[0892] b) flow diagrams, FIGS. 12 through 23, showing the functional interaction among the system, the enabler and the medical professional;

[0893] c) some of the actual screens that the MP views during an arrest (The complete set of screens consists of FIGS. 24-44. Ten of the 19 screens are mentioned in Table 11.);

[0894] d) the handshakes, discussed above and summarized in Tables 7, 8 and 9; and

[0895] e) the confirmation signals which let the MP know that his commands were properly executed.

[0896] Explanatory comments in the table are indented.

[0897]

TABLE 11
Events During an Hypothetical Cardiac Arrest
		Flow	CS
Time		Diagram	Console
m:ss	Event	Fig#	FIG.#
Phase One
0:00	Enabler (EN) sees emergency victim
	(VI) and decides to help
0:01	EN heads for nearest Portable Unit
	(PU)
0:31	Button press by EN	12
Phase Two
0:31	PU transmits handshake (HS) signals	12	25
	to Central Station (CS)
0:32	Completion of Communication HS	12	25
	between PU and CS	13
	(Table 7, VI-MP Link, HS #1)
0:32	Completion of Data/Command HS between	14	25
	PU and CS
	(Table 7, HS #2)
0:32	CS identifies PU as Unit #643025,
	located in Columbus, Ohio
0:33	MP identifies himself	15
0:37	EN confirms that he can hear the MP;
	MP confirms that he can hear the EN;	15	25
	These constitute completion of
	Audio HS between EN and MP
	(Table 7, HS #3A and #3B)
0:41	MP asks EN to describe the emergency	16A
0:44	Begin EN's description of the	16A
	emergency
0:50	End EN description;	16A
	MP decides that this emergency
	warrants intervention by MP and PU
	This constitutes completion of
	Informational HS between EN and MP
	(Table 7, HS #4)
Phase Three
0:50	MP issues commands to	16A	27
	a) release PU lock
	b) call 9-1-1 nearest to EN
0:50	CS transmits and PU receives	16A	44
	Lock Release Command	24
0:51	Electromagnetic Lock releases PU from	16B
	Stationary Unit (SU)
0:51	PU transmits and CS receives lock	16B	44
	release confirmation	24
0:52	MP sees lock release confirmation		27
0:53	MP tells EN to detach PU from SU,	16C	27
	and to transport PU to VI
0:55	EN detaches PU from SU;
0:55	PU transmits and CS receives and	24	44
	displays PU removal telemetry signal
0:56	MP sees removal telemetry signal	16C	27
0:56	EN transports PU to VI;	17
	During transport, MP provides EN
	with additional instructions
0:56	During transport, there is continuous		25
	updating of the link between EN and
	MP
1:37	EN tells MP that he has arrived at	18A
	VI's side
1:39	MP tells EN how and where to put PU	18A
	down
1:41	EN puts down PU; This automatically	18A	44
	releases tool-kit door and transmits	24
	PU touchdown telemetry signal; CS
	receives and displays telemetry
1:42	MP sees PU touchdown telemetry signal;	18A	27
	On PU Deployment Screen, MP presses		28
	GO TO VIDEO CONTROL SCREEN; This
	Brings up Video Control Screen
1:42	MP optimizes audio to and from EN	18B	44
1:46	MP asks EN if VI is unconscious;	18D
	VI answers affirmatively
1:48	MP, working from Video Control Screen,	18A	28
	extends video boom, so its end
	protrudes from PU
1:50	MP instructs EN in exposing VI's	18E	28
	chest
2:00	MP determines that pad 204B is	18E	28
	optimal (5 large/7 small electrodes)
	and tells EN to get it from top shelf
	of tool-kit
2:05	EN pulls pad 204B, and the cable and	18E	28
	Universal Connector which attach pad
	to the PU, from the tool-kit shelf
2:07	MP instructs EN in proper pad	18E	28
	location, orientation, and
	application method
2:09	EN peels off pad cover; Cover removal	24	44
	telemetry signal is transmitted by PU
	and is received and displayed by CS
2:11	EN applies pad to VI's chest
2:14	MP sees that pad is properly placed;	18F	28
	On Video Control Screen, MP presses		29
	INITIAL ECG SCREEN; This brings up
	Initial ECG Screen
2:15	MP observes adequate impedance value	18F	29
	for each pad electrode
	This constitutes Part A of the
	Electrical HS between VI and MP
	(Table 9, VI-MP Link, HS #3A)
2:17	MP notes that ECG is of good quality	18F	29
	on Initial ECG Screen
	This constitutes part B of the
	Electrical HS between VI and MP
	(Table 9, HS #3B)
2:17	MP diagnoses ventricular fibrillation	19	29
	This constitutes the informational
	HS between VI and MP
	(Table 9, HS #4)
Phase Four
2:18	MP selects MAIN DEFIB SCREEN on		29
	Initial ECG Screen; This brings up		33
	Main Defib Screen
2:18	MP tells EN to avoid contact with VI	20
	due to impending defibrillator shock
2:19	MP decides to use default defibrillation
	parameters (i.e. α and δ pads)
2:20	MP selects ALL DEFAULT VALUES, then	20	33
	selects ACCEPT on Main Defib Screen
2:20	CS transmits and PU receives command	24	44
	to begin charging PU defibrillator
	capacitors; charging begins
2:23	Capacitor charging complete; PU sends	24	44
	and CS receives and displays charge
	completion confirmation
2:25	MP notes charge completion signal,	20	24
	confirms persistence of VF, and		ECG
	issues command to deliver shock by		33
	selecting DELIVER on Main Defib
	Screen
2:25	CS transmits shock command to PU;	24	44
	PU receives command and delivers
	default shock to VI
2:25	PU sends, and CS receives and	24	44
	displays shock confirmation data
2:26	MP notes confirmation and notes	19	24
	persistence of VF, post-shock		ECG
2:27	MP decides to deliver another	20
	defibrillating shock
2:28	MP tells EN to avoid contact with VI	20
	due to impending defibrillator shock
2:29	MP decides to alter defibrillation	20
	vector (by using the α and ε pads)
	to enhance chance of success of
	next shock)
2:30	MP selects OTHER under ELECTRODES	20	33
	on Main Defib Screen; This brings up		31
	Five Electrode Setup Screen
2:31	MP selects α, ε electrode pair on Five	20	31
	Electrode Pad Setup Screen by		33
	touching the following sequence:
	1) α
	2) ε
	3) ACCEPT
	This brings up Main Defib Screen
2:33	On Main Defib Screen, MP selects	20	33
	additional parameters of upcoming
	second defibrillator shock by
	touching the following sequence:
	1) MAX under ENERGY
	2) NO under SYNCH
	3) DEFAULT under WAVEFORM
	4) ACCEPT
2:35	CS transmits and PU receives commands	24	44
	to switch to α, ε pair of defibrillator
	electrodes and to begin charging PU
	defibrillator capacitors;
	charging begins
2:38	Capacitor charging complete; PU sends	24	44
	and CS receives and displays charge
	completion confirmation
2:40	MP notes charge completion signal,	20	24
	confirms persistence of VF, and		ECG
	issues command to deliver shock by		33
	selecting DELIVER on Main Defib
	Screen
2:40	CS transmits shock command to PU;	24	44
	PU receives command and delivers
	second shock to VI, via α and ε pads
2:40	PU sends, and CS receives and	24	44
	displays shock confirmation data
2:43	MP observes termination of VF and	19	ECG
	notes presence of asystole (flat line);
	MP decides to begin pacing the heart,
	to accelerate the heart rate
2:44	MP selects MAIN PACING SCREEN on	23	33
	Main Defib Screen; This brings up		38
	Main Pacing Screen
2:46	MP selects ALL DEFAULT VALUES; then	23	38
	selects DELIVER on Main Pacing Screen
2:46	CS transmits command to PU to begin	24	44
	pacing at 60 BPM (pacing mode, pulse
	width, amplitude and pad choice are
	also specified in the command)
2:46	PU receives commands and begins	24	44
	pacing at 60 BPM
2:46	PU sends, and CS receives and	24	44
	displays pacing confirmation data
2:48	MP notes pacing at 60 BPM		ECG
2:48	MP instructs EN to remove blood	22
	pressure cuff and oximetry sensor
	from tool-kit and apply them to VI
2:49	From Screen Menu, MP selects VIDEO		44
	CONTROL SCREEN; This brings up		28
	Video Control Screen from which MP
	Displays instructional video for EN
2:56	MP observes that victim's blood pressure		BP
	is 80/50 (low) and that the oxygen		SAT
	saturation value is 96% (adequate)
2:57	MP decides to reduce pacing rate in
	order to: a) observe victim's underlying
	rhythm; and b) in attempt to
	increase victim's blood pressure by
	restoring atrioventricular synchrony
2:57	MP selects OTHER next to RATE on	23	38
	Main Pacing Screen;		40
	This brings up Bradycardia Pacing
	Rate Screen
2:58	MP touches 55, followed by ACCEPT	23	40
	on Bradycardia Pacing Rate Screen;		38
	This returns Main Pacing Screen
2:59	MP sets default values for other	23	38
	pacing parameters by touching:
	1) DEFAULT under AMPLTIUDE
	2) DEFAULT under WAVEFORM
	3) DEFAULT under PACING
	ELECTRODES
	4) DEFAULT under SENSING
	5) DELIVER
3:01	CS sends command to PU to change	24	44
	pacing rate from 60 to 55 BPM
3:01	PU receives command and changes	24	44
	pacing rate to 55 BPM
3:01	PU sends, and CS receives and	24	44
	displays pacing confirmation data
3:04	MP observes emergence of victim's own	19	ECG
	normal sinus rhythm at 58 BPM
3:05	MP decides that pacing is no longer		38
	necessary and touches STOP PACING on
	Main Pacing Screen
3:05	CS sends command to PU to stop pacing	24	44
3:05	PU receives command and stops pacing	24	44
3:05	PU sends, and CS receives and	24	44
	displays stop pacing confirmation
3:07	MP observes that pacing has ceased		ECG
3:18	MP observes that victim's blood		BP
	pressure has risen to 100/60
	The victim's heart rate, rhythm
	blood pressure are now considered
	to be adequate.
Phase Five
3:18	MP asks EN to obtain VI's name and
	other identifying data, from persons
	accompanying the VI, from the VI
	himself, or from VI's wallet
3:24	EN provides MP with VI identification
3:27	MP enters VI identification into
	Archival Database
3:31	MP views display of VI past medical
	history, obtained from databases
3:36	MP informs EN that estimated time of		27
	arrival of local Emergency Medical
	Team (EMT) is in four minutes
Phase Six
7:25	Arrival of EMT
7:27	MP identifies himself to EMT
7:31	EMT says that they can hear the MP;
	MP confirms that he can hear the EMT;
	These constitute completion of
	Audio HS between EMT and MP
	(Table 10, HS #3A and #3B)
7:35	MP asks EMT for password;
	EMT's knowledge of password proves
	they are qualified to take over
	management of the case from the MP
7:39	EMT provides password
7:43	MP confirms that password is correct,
	i.e. it indicates a qualified EMT;
	MP decides to transfer control of PU
	To EMT
	This constitutes completion of
	Informational HS between EMT and MP
	(Table 10, HS #4)
Phase Seven
7:43	MP informs EMT that password has been
	confirmed and that control of the PU
	will now be transferred to the EMT
7:47	On the Communications Status and		25
	Triage Screen, MP selects GO TO EMT
7:47	CS transmits command to change the	24	44
	Master Control Unit state from its
	present value of 1 (MP control of
	the PU) to 3 (allowing EMT control
	of the PU); PU receives command
	(Table 1)
7:47	Master Control Unit 130 changes	24	44
	state, allowing EMT control of PU;
	PU sends, and CS receives and displays
	change of state confirmation
	The transfer of control of the PU
	from MP to EMT is now complete;
	EMT can now control PU, using the
	same screens that MP was using
7:48	MP briefs EMT about current victim
	status, about events that have
	transpired during the past eight
	minutes, and about victim's medical
	history and identification, if known
Beyond this point, the MP role and time allocations are highly variable and are discussed in Sections 4.17, 4.18, 4.45, and 4.57. Phase seven ends when both: a) the PU is disconnected from the victim; and b) the PU is returned to the SU.

4.3 Role of the Medical Professional
4.3.1 Expert Decisions Made by the MP During the Cardiac Arrest

[0898] One very important role of the MP is the making of expert management decisions. The expertise and judgment of the MP and the flexibility and capability of the system allow the resuscitation procedure to be performed as if a medical doctor specializing in heart rhythm disorders, or a highly trained emergency medical technician was actually present at the emergency scene. Three examples of major MP decisions, which occur during the sample arrest, are: a) the MP decision to change the defibrillation vector for the second shock, and the capability of the system and the electrode pad to accommodate the decision; b) the MP ability to reliably distinguish asystole from VF post second shock and his decision to begin bradycardia pacing at that time; and c) the MP decision to slow the pacing rate from 60 to 55, in an attempt to improve the blood pressure by restoring AV synchrony. These three examples will now be discussed, to be followed by a discussion of other significant MP management decisions.

4.3.1.1 The MP Decision to Change the Defibrillation Vector for the Second Shock

[0899] Our present understanding of the physiology of defibrillation is that the high voltage discharge depolarizes a significant fraction of the cardiac tissue. The shock thus momentarily prevents the propagation of the multiple fibrillatory wavefronts that are the basis of VF, and thereby causes the termination of VF. Since VF is a metastable heart rhythm, momentarily interrupting it allows for the emergence of a generally more stable rhythm, the heart's normal (or sinus) rhythm.

[0900] However, if the electrode pads are located in positions that do not allow the shock to depolarize enough of the fibrillating heart muscle, the shock is ineffective and VF persists despite the shock. It is therefore common procedure, during the conduct of an actual VF resuscitation, for the physician or other properly trained person to select alternate electrode pad positioning, if one or more shocks fail. Such repositioning is most likely to be necessary in the case of either a large victim, or in certain medical disease states where the heart itself has enlarged considerably. In the preferred embodiments which utilize multi-electrode pads, the MP can accomplish electrode repositioning electronically. In the case of the five electrode pad, shown in FIGS. 5A-E, the MP accomplishes the desired repositioning by simply selecting the more laterally located ε electrode, in place of the previously ineffective δ electrode. The fact that the α,ε pair of electrodes encompasses a greater amount of cardiac tissue than the standard α,δ pair makes it more likely to be effective.

[0901] The MP has a variety of options to choose from in the event of an ineffective shock for VF. They include:

[0902] a) simply repeating the shock without changing any parameters;

[0903] b) changing the shock vector, i.e. changing the anatomic relationship between electric current flow and the heart's position, as was done for the second shock in the example discussed;

[0904] c) increasing the energy of the shock;

[0905] d) changing the waveform of the shock, and

[0906] e) instructing the enabler in the performance of CPR, and then shocking the victim.

[0907] State of the Art AED systems do not have the flexibility to accomplish the five options listed above. Furthermore, if they did have one or more of these options, they would not be endowed with the superior ability of a highly trained professional to choose which among the options would be ideal. However, utilizing a preferred embodiment of this invention, a medical professional would have all of these options and be in a position to choose intelligently from among them. Based on his judgment, the MP might be more inclined to choose the second option, i.e. a shift in electrode location, if he:

[0908] a) noted that a previous shock using standard electrode positioning was ineffective;

[0909] b) knew from video observation (or enabler description) that the victim was large;

[0910] c) knew from video observation that the multi-electrode pad had not been positioned perfectly at the time that the enabler placed it on the victim's chest; and/or

[0911] d) knew, from either accessing the database or from a person accompanying the victim, that the victim's medical history included an enlarged heart or a medical condition or diagnosis associated with an enlarged heart. (In the scenario in Table 11, the database is not accessed until after the resuscitation is complete, but it could have been accessed earlier.)

4.3.1.2 MP Distinction Between Asystole and Ventricular Fibrillation

[0912] The second example of the combination of MP expertise and judgment and the invention's flexibility and capability resulting in a successful outcome, relates to the MP diagnosis of asystole following the second shock. Asystole, the absence of any cardiac electrical activity can occur after a successful defibrillation shock. It is more likely to occur after a long duration of VF, than after a brief episode. At times, the electrocardiographic distinction between VF and asystole is subtle. Although the “textbook” electrocardiogram (ECG) of VF consists of a continuously varying high frequency, low amplitude oscillation, and the “textbook ECG of asystole is a perfectly flat, featureless line, at times one sees ECG tracings which might be described as falling in-between the aforementioned textbook descriptions. For example, during the phenomenon known as “fine VF,” the ECG undulations are so low in amplitude that the tracing may be misread as asystole. And during some episodes that actually are asystole, the baseline may wander enough (either due to jostling of the victim, the pad or the cable, by the resuscitation team) so that even an expert cardiologist is uncertain about whether to read the ECG as asystole or fine VF.

[0913] The diagnostic problem is compounded by the fact that the treatment for VF is entirely different than the treatment for asystole. Fine VF is treated by administering a defibrillator shock. Asystole is treated by pacing the heart. A defibrillator shock is useless for asystole and pacing the heart is impossible during VF. Thus the distinction between the two rhythms is of much more than academic interest.

[0914] In principle, an algorithm could be created which could distinguish between these two rhythms as well as an expert professional. The reality is, that as of the current time, no algorithm with the discriminating power of the most expert professional exists.

[0915] If the distinction between these two rhythms is especially difficult, the options available to the MP using a preferred embodiment of the current invention include one or more of the following:

[0916] a) recording for a longer period of time, in order to have a larger information sample;

[0917] b) asking enabler to make sure that no individual is, for the moment in contact with the victim or the cable between the victim and the PU;

[0918] c) causing the PU to sample the ECG more frequently than it does with nominal settings, resulting in more accurate ECG reproduction (In a preferred embodiment the system, according to the invention, all information is transmitted between the central station and the portable unit in digital form.);

[0919] d) digitizing the ECG signal with a greater number of bits per sample, resulting in more accurate ECG reproduction;

[0920] e) increasing the bandwidth allocated for transmission of ECG information, either (i) on the already established communication channel between the PU and the CS, or (ii) by establishing an additional channel;

[0921] f) switching ECG transmission temporarily to a non-real time format in which: (i) the amount of ECG information recorded per unit time is increased (by increasing either the sampling rate or the number of bits per sample), (ii) the information is temporarily stored in a buffer, and (iii) the information is transmitted over the nominal bandwidth allocation;

[0922] g) encoding the ECG information differently, using a real time format;

[0923] h) setting up another communication channel between PU and CS and transmitting an analog version of the ECG signal i) in the event of a degraded ECG signal due to distortion due to communication problems, comparing the MP rhythm analysis with that of the on-site AED/P logic unit, 128;

[0924] j) making the decision to empirically shock the victim, i.e. making the assumption that the rhythm is fine VF; and

[0925] k) making the decision to empirically pace the victim, i.e. making the assumption that the rhythm is asystole.

[0926] Options (c), and (d) involve recording a reproduction of the ECG signal. Option (a) also provides more (but not more accurate) information for the MP. Options (f), (g) and (h) involve changes in the format for ECG encoding. Option (i) would be useful if the MP still had diagnostic uncertainty, despite any of the options (a) through (h) directed at providing the MP with more or higher quality ECG information.

[0927] In the scenario described in Table 11, the MP was able to make the distinction, correctly diagnosing asystole at 2:43 and instituting cardiac pacing as of 2:46.

4.3.1.3 MP Effort to Improve Blood Pressure

[0928] The third example of MP expertise and judgment combining favorably with the invention special features involves the MP commands at 2:57 to reduce the pacing rate. Proper management by the MP, in this scenario, involved giving consideration to the possibility that the low blood pressure (80/50) during pacing may have been caused or accentuated by the pacing itself. This phenomenon is not uncommon and is sometimes referred to as pacemaker syndrome. This syndrome may occur when pacing the heart results in an unnatural sequence of electrical activation of the four heart chambers, resulting in suboptimal mechanical performance. It may result during external pacing because such pacing cannot sequentially stimulate the atria followed by the ventricles.

[0929] In normal individuals, the atria contract first and the ventricles contract 0.12 to 0.20 seconds later. Optimal cardiac function is often associated with the proper sequence and timing of electrical activation of the heart. When atrial contraction precedes ventricular contraction, referred to as atrioventricular or AV synchrony, a number of mechanical advantages obtain including: a) an increase in the pre-contraction volume of the ventricles, meaning more blood is available to be pumped; and b) an increase in the pre-contraction ventricular wall tension, which optimizes ventricular mechanical contraction. The decrease in cardiac mechanical performance resulting from the loss of AV synchrony is quite variable from person to person; in some persons the decrease is trivial, in others it is profound.

[0930] In the arrest described in Table 11, pacing was necessary because of asystole following the second defibrillation shock. It would not be unusual for a heart, which just suffered through some minutes of the oxygen and nutrient deprivation of a cardiac arrest, to exhibit depression of electrical and mechanical function. Although external pacing can stimulate the ventricles and thereby remedy the asystole, it can not stimulate the atria and ventricles in proper sequence. The low blood pressure which follows (MP becomes aware of it at 2:56.) may be due to a combination of both of the aforementioned factors: a) pacemaker syndrome due to loss of AV synchrony; and b) depression of mechanical function post arrest. MP options at that juncture would be: a) lower the pacing rate; b) increasing the pacing rate (to try to stimulate the heart to pump more blood, albeit at a lower pressure); or c) leaving the pacing rate as is. This is a clinical decision, often made by cardiologists and cardiac rhythm specialists. The decision is based on many factors including the presence, if any, of ongoing rhythm instability (as evidenced by premature beats, for example), the victim's past medical history, and other clinical parameters.

[0931] The logic behind lowering the pacing rate is that after a short period of pacing for asystole, the heart may recover enough to have its own pacemaker cells resume functioning. As such a recovery ensues, the cells may begin to fire slowly at first, and then have their rate gradually normalize. However, if external pacing is occurring at a rate which is greater than the rate at which the heart's pacer cells are firing, ventricular activation will be preempted by the stimulus from the external pacer. By lowering the pacing rate, the MP can determine: a) if such a recovery is occurring, and if it is; b) whether allowing the victim's rate to fall so that the heart's pacemaker cells can “take over” and so that AV synchrony can resume, results in a more favorable blood pressure.

[0932] The decision is a complex one because lowering the heart rate may, in some victims, promote the emergence of greater instability, either electrical (i.e. heart rhythm related) or mechanical (blood pressure decline). In a worst-case scenario it could lead to another arrest. This underscores the value of having an expert make such decisions.

4.3.1.4 Other MP Decisions Requiring Medical Expertise

[0933] Other decisions made by the MP (and unrelated to his interaction with either the enabler [see Section 4.3.2] or the EMT [see Section 4.3.3]) during the sample arrest which require medical expertise include:

[0934] a) the choice of which particular electrode pad to use (occurs at 2:03 during the sample arrest);

[0935] b) defibrillation parameters other than the choice of which electrodes to use, such as energy, pulse configuration, synchronization (occurs at 2:19 and 2:33 during the sample arrest);

[0936] c) pacing parameters other than the choice of which pacing rate to use, such as pulse width, amplitude, electrode choice (occurs at 2:46 during the sample arrest); and

[0937] d) the duration of pacing (occurs at 3:05 during the sample arrest).

[0938] Other MP decisions which require expertise, might need to be made during another arrest, but which were not needed during the sample arrest include:

[0939] a) when to choose antitachycardia pacing (a form of rapid pacing intended to terminate certain tachycardias) instead of administering a shock;

[0940] b) the parameters of antitachycardia pacing (see FIG. 37) including the initial rate of pacing, the number of paced beats, the interval between successive paced beats, the interval between last victim beat and first paced beat, the pulse width, and the pulse amplitude;

[0941] c) the number of antitachycardia pacing attempts;

[0942] d) the change, if any, in antitachycardia pacing parameters from one attempt to the next;

[0943] e) the decision, in the case of a victim who is known to have an implantable cardioverter defibrillator or “ICD,” about whether to let his ICD treat a rhythm abnormality, or whether MP should perform preemptive therapy;

[0944] f) the decision about when to begin CPR (see Section 4.5.5.1);

[0945] g) the decision about when to terminate CPR;

[0946] h) the decision, if on-site physicians and/or EMT are unavailable, about when to terminate all therapy (see Sections 4.5.3.2 (b), 4.5.5.2 (i) and 4.5.7.8.1 (d)).

4.3.2 Enabler Guidance by the MP

[0947] The aforementioned MP decisions illustrate the value of the MP for decision-making capability at the level of an expert cardiac rhythm specialist. There are other MP actions, which guide the performance of the enabler, which are also important. These include: a) proper application of the electrode pad; b) cardiopulmonary resuscitation; and c) a number of other enabler actions.

4.3.2.1 Enabler Guidance in Proper Application of the Electrode Pad(s)

[0948] Proper electrode pad positioning is critical for reasons previously mentioned. In brief, the shock must be delivered between two electrodes that are situated, approximately, on opposite sides of the heart. The greater the deviation from such positioning, the less the chance that a shock will be successful. Although multi-electrode pads like the five electrode pad and the matrix pad allow the MP to compensate for minor or moderate errors in pad application or orientation, the MP is less likely to be able to correct for gross errors.

[0949] The MP has multiple options for instructing the enabler in the placement of electrode pad(s). The MP may verbally instruct the enabler as he applies the electrode pad(s). The MP may visually instruct the enabler by showing him a live video of the victim's torso, upon which MP has superimposed visual prompts such as arrows, an outline of the pad, or a cartoon version of the pad. If the PU and video boom are situated such that superimposition of visual prompts is impractical, the MP may show still or moving images, kept on file, which illustrate proper pad application.

[0950] During the sample arrest presented in Table 11, the MP guides the enabler in electrode pad application at 2:07. The adequacy of the application is assessed at 2:15 and 2:17 (see Table 11 and Section 4.5.3.3).

4.3.2.2 Enabler Guidance in Cardiopulmonary Resuscitation

[0951] Cardiopulmonary resuscitation is another procedure for which the MP can provide instruction and guidance. Although not included in the scenario in Table 11, CPR is a common procedure during cardiac arrests attended by emergency medical teams. CPR consists of a rhythmic series of properly timed chest compressions intended to propel blood through the circulatory system. In addition, as its name implies, CPR may include means to move air in and out of the victim's lungs, a process referred to as ventilation. The person or persons who perform CPR (hereinafter referred to as “resuscitating person(s)”) may be: a) the enabler; b) anyone else at the scene of the cardiac event; or c) a combination of the enabler and another resuscitating person.

[0952] The chest compressions are performed by rhythmically pressing down over the victim's sternum, or breastbone. There are also experimental devices intended to accomplish a similar result.

[0953] Ventilation may be accomplished by properly placing a mask over the victim's mouth and nose, and squeezing an attached bag which pumps air into the lungs; the weight of the chest wall and the elasticity of the lungs result in the expulsion of the air without the need for active external intervention. Another ventilation option is so called “mouth to mouth” resuscitation, during which a resuscitating person places his mouth over the victim's mouth (or upon a device interposed between his mouth and the victim's mouth), and blows air into the victim's lungs. At times, chest compression is performed without such ventilation.

[0954] The need for CPR will depend on both the cause of the cardiac arrest and the amount of time between the onset of the rhythm abnormality and its remedy. The success rate for defibrillation without CPR, when the defibrillation takes place very quickly after the onset of VF, is very high. The longer the elapsed time until defibrillation, the greater the likelihood that CPR will be necessary. The need for CPR may be determined in each of the following ways:

[0955] a) CPR will need to be administered if, at the time of the initial recording, the victim's electrocardiogram shows that the rhythm is normal, but the blood pressure or oxygen saturation readings are, in the opinion of the MP, unacceptably low.

[0956] b) CPR will need to be administered if, post-shock or post-pacing, after an initially abnormal rhythm has been normalized, the blood pressure or oxygen saturation readings are, in the opinion of the MP, unacceptably low.

[0957] c) CPR will need to be administered if ventricular fibrillation or tachycardia is present which is not responding to electrical shocks.

[0958] d) In addition there is more recent evidence to suggest that CPR may even have a beneficial effect immediately before the administration of a first defibrillating shock.

[0959] The MP can assist the enabler and/or other resuscitating person in the performance of CPR in each of the following ways:

[0960] a) Using means similar to those for illustrating proper electrode pad application, the MP may use one of the PU screens 156 to illustrate where on the chest the resuscitating person must apply pressure. Screen use may entail images superimposed on that of the victim, or previously prepared instructional video materials.

[0961] b) The MP may use PU screens 156 to illustrate other aspects of chest compression including the proper relation between the resuscitating person's right and left hands, and the proper body position for the resuscitating person.

[0962] c) The MP may coach the resuscitating person during the performance of chest compression. Such coaching may address the rate of compression and the vigor with which it is performed.

[0963] d) Because the mechanical disruption caused by chest compression often interferes with the ability to record a high quality electrocardiogram, the MP may, from time to time, ask the resuscitating person to suspend chest compression for a few seconds. During such time, the ECG signal is clearer; such interruptions give the MP a better view of the rhythm status during chest compression.

[0964] e) The MP may also, from time to time, request a pause in chest compression to recheck the victim's blood pressure. This check must occur in the absence of chest compression, since chest compression would mask the victim's cardiac performance.

[0965] f) Using means similar to those for illustrating proper electrode pad application, the MP may use one of the PU screens to illustrate proper ventilation technique.

[0966] g) During ventilation, the MP may coach the resuscitating person as to the proper rate of ventilation. Such coaching would also address the way that chest compression and ventilation should be coordinated. (The manner of coordination is different when there are two resuscitating persons, as opposed to a single resuscitating person.)

[0967] h) Using oxygen saturation data from a sensor which has been applied to the victim by the enabler, the MP will be able to have some indication as to the adequacy of ventilation. The MP may use this information to give further guidance to the resuscitating person(s).

[0968] i) The presence of airway pressure and flow monitoring sensors within either a mask (part of the bag and mask ventilating apparatus) or within a device interposed between the resuscitating person's mouth and the victim's mouth would give the MP another way of determining the adequacy of ventilation (see Section 8.8). The MP may use this information to guide the resuscitating person in his use of the ventilating apparatus.

[0969] j) Ventilation adequacy could also be monitored by measuring the impedance between chest electrodes. Since air has a lower conductivity than body fluids, as the chest inflates with air, impedance across the chest increases. Certain implanted pacemakers, as are known in the art, perform such measurements within the body, in order to determine ventilation status. The MP may use such impedance information to guide the enabler or other resuscitating person in his use of the ventilating apparatus (see Section 8.9).

[0970] k) Finally, during the performance of CPR, there is enough uncertainty and hesitancy on the part of all but highly experienced emergency personnel, that any reassurance that can be provided during CPR is an asset.

[0971] It should be noted that: a) CPR is not required during all resuscitations; and b) even in a situation where enabler and anyone else at the scene is either unwilling or unable to do CPR (or is unable or unwilling to perform chest ventilation), the ability of the invention to provide MP expertise in performing the electrical part of the resuscitation and other functions is expected to be of substantial value.

4.3.2.3 Enabler Guidance in Other Activities

[0972] Other ways in which the MP can guide the enabler, facilitating the performance of enabler tasks include:

[0973] a) guiding the enabler in properly positioning the PU near the victim (occurs at 1:39 during the sample arrest);

[0974] b) guiding the enabler in removing victim clothing which may prevent access to the chest (occurs at 1:56 during sample arrest), discussed below in section 4.5.3.3;

[0975] c) guiding the enabler in properly applying the blood pressure and oxygen saturation monitoring devices (occurs at 2:48 during sample arrest), discussed below in section 4.5.4.2;

[0976] d) guiding the enabler, post EMT arrival, during certain activities aimed at making the PU ready for its next use, hereinafter referred to as “housekeeping” (see Section 4.5.7.3, below);

[0977] e) guiding the enabler, post EMT arrival, in reattaching a PU to the SU (see Section 4.5.7.4, below); and

[0978] f) reassuring the enabler during the commotion and pandemonium that may accompany a cardiac arrest (occurs intermittently throughout the MP-enabler interaction).

4.3.3 EMT and Physician Guidance by the MP

[0979] The role of the MP expands, once the EMT arrives. MP responsibilities then include:

[0980] a) properly identifying the EMT;

[0981] b) briefing the EMT about the victim's current condition and the events that transpired during the previous minutes (see Section 4.1.7.2);

[0982] c) instructing the EMT in PU operation, if necessary (see Section 4.1.7.4.1);

[0983] d) providing heart rhythm related diagnostic and management advice, if necessary (see Section 4.1.7.4.1);

[0984] e) providing pharmacologic advice (see Section 4.1.7.4.2); and

[0985] f) providing guidance about cessation of therapy.

[0986] As indicated above (see Section 4.1.8), the MP guidance role may also include providing historical, diagnostic and management advice for the physician(s) to whom the EMT transfers to victim.

4.4 Time Allocation During the Sample Cardiac Arrest

4.4.1 General Considerations Regarding Prediction of Duration

[0987] Time allocations during the sample arrest are estimates, based on the experience of the inventor. For some events, such as the time it takes the MP to correctly read an electrocardiogram, the actual duration is expected to deviate little from the estimated duration, under most circumstances. (Hereinafter, the extent of deviation of actual durations from estimated values is referred to as “the variance.”) For other events, such as transporting the PU, substantially greater variance is expected. Finally, there are certain events such as the duration of phase seven, where the variance is so great, that no attempt has been made to predict event duration.

4.4.2 Enabler Travel Time

[0988] Nearly all of phase one in the hypothetical arrest represents the time it takes the enabler to reach the portable unit. The amount of time will be a function of both: a) the distance between the victim and the PU; b) the walking/running speed of the enabler; and c) the enabler's ability to determine where the nearest PU is located. Thirty seconds is assumed; The enabler (assuming a speed of 3.5 miles per hour) is expected to be able to walk approximately 50 yards in this time. It is therefore possible that phase one could be substantially shorter or longer than the allotted 31 seconds.

[0989] The return trip, i.e. enabler's transport of the PU from its attachment to the stationary unit (which may be wall mounted) is also of variable duration. The duration will be determined by: a) the distance between the PU and the victim; and b) the enabler's speed while carrying the PU. If we assume that the enabler transports the unit moving slightly slower than he did without having to carry the PU (2.5 miles per hour is assumed), and if we again assume an approximately 50 yard distance, the time required will be 41 seconds. The total transport time for the PU is thus assumed to be approximately 71 seconds.

4.4.3 Duration of Other Enabler Tasks

[0990] Though virtually every event which requires enabler action will vary in duration, depending on the particular enabler and event, some event durations are less predictable than others. Enabler events whose variances may be substantial include:

[0991] a) enabler's description of the emergency for the MP;

[0992] b) enabler's baring the chest of the victim;

[0993] c) enabler's application of the electrode pad to the victim;

[0994] d) enabler's application of blood pressure and oxygen saturation measuring equipment to the victim; and

[0995] e) enabler's identifying the victim.

[0996] Enabler events with a lesser degree of variance include:

[0997] a) enabler's initial decision to help the victim;

[0998] b) the audio handshake between the enabler and the MP;

[0999] c) removing the PU from the SU; and

[1000] d) orienting the PU video boom.

4.4.4 Time Allocation for MP Tasks During Phase Four

[1001] Although the duration of individual MP actions is far more predictable than the duration of either enabler or EMT actions, the number of therapeutic MP actions required to resuscitate a victim is highly uncertain. Four MP interventions (two shocks, and two different bradycardia pacing efforts) were included in the hypothetical arrest scenario presented here. If only a single defibrillating shock had been required to restore a normal rhythm, that restoration would have occurred at 2:26 into the arrest. The second shock added another 17 seconds; and the need for pacing added another 19 seconds.

[1002] The second shock and the pacing thus add another 36 seconds to the time until normal rhythm is restored. These 36 seconds, when added to the aforementioned 71 seconds of variable transport time, total up to one minute and 47 seconds. Thus more than half of the time until normal rhythm is restored in the current scenario, must be considered to be substantially variable.

4.4.5 Time Allocation Involving EMT Events

[1003] Two EMT related time estimates are also highly variable. The first concerns the time that it takes the EMT to arrive. Arrival at 7:25 (which is six minutes and thirty five seconds after being called by the MP) is a realistic value for some areas of the United States. The time of EMT arrival is one of much reduced importance, because the definitive treatment for the arrest occurs substantially before such arrival. The second highly variable EMT event is the duration of phase seven, and the individual events which comprise it. Since both the duration and the number of phase seven events is highly variable (in part related to regional aspects of EMT policy and procedure), no attempt has been made to predict the duration of phase seven.

4.4.6 Correction for Simultaneous or Nearly Simultaneous Tasks or Events

[1004] Another time-related issue is that certain MP tasks may appear to have a surprisingly short time earmarked for their performance. This is because some of these tasks, though listed in the table as sequential, are expected to be performed simultaneously. For example: during phase three, the MP could adjust the video boom (allocation in Table 11 is 1:54 to 1:56) and instruct the EN (allocated for 1:56 to 2:03) simultaneously. Therefore, the time to do the video adjustments is really from 1:54 to 2:03, not from 1:54 to 1:56. There are many other examples of this overlap phenomenon. There are also instances of events which overlap, and of events and tasks which overlap; in each instances, appropriate adjustment of estimate duration has been made.

4.5 Further Details Concerning Specific Issues During the Sample Cardiac Arrest

[1005] What follows is a discussion of specific events and issues during the aforementioned hypothetical arrest.

4.5.1 Phase One: Amount of Time for Enabler to Reach PU

[1006] This is dependent on a number of factors and is discussed in 4.4, above.

4.5.2 Specific Issues During Phase Two

4.5.2.1 Initial and Subsequent MP Screens

[1007] At 0:31, as the initial handshake is occurring between the enabler and the MP, the MP console in the central station immediately changes to reflect the new event. In the scenario described in Table 11, three MP screens are activated without the MP needing to select them: a) the Communications Status and Triage Screen, FIG. 25 (first noted in Table 11 at 0:31); b) the Portable Unit Deployment Screen, FIG. 27 (first noted at 0:51); and c) the Confirmations Screen, FIG. 24 (first noted at 0:51). These screens allow the MP to perform the initial operations during the early period of his interaction with the enabler.

[1008] The MP selection of new screens can occur in one of five ways:

[1009] a) Most screens generally have touch-selected choices for each other screen that may be needed next. Thus the PU Deployment Screen, FIG. 27, has a GO TO VIDEO CONTROL SCREEN button, since the Video Control Screen is the screen likely to be the one from which the MP works, after finishing with the PU Deployment Screen Similarly, the Video Control Screen, FIG. 28, has an INITIAL ECG SCREEN button, since the latter screen is likely to follow the Video Control Screen. The Initial ECG Screen, FIG. 29, lets the MP navigate to any one of the three screens likely to be needed next; the Main Pacing Screen, FIG. 38; the Main Defibrillation Screen, FIG. 33; and the Antitachycardia Pacing Screen, FIG. 37. The Antitachycardia Pacing Screen allows one-touch navigation to the Main Pacing and Main Defibrillation Screens. The Main Pacing and Main Defibrillation Screens each allow one-touch navigation to multiple other screens, each of which deals with one particular parameter of pacing (e.g. rate) and defibrillation (e.g. energy).

[1010] b) Each of the screens which deal with individual pacing and defibrillation parameters allows rapid transit back to Main Pacing or Defibrillation Screens, by pressing ACCEPT.

[1011] c) The Screen Menu, FIG. 44, can be accessed at any time by pressing a “hot key” or keys (e.g. Control, S) on the MP keyboard. When this is done, the Screen Menu appears on one of the MP touch sensitive screens. This menu provides access to every possible MP screen.

[1012] d) The Screen Menu can also be accessed directly from a number of other screens, e.g. the Five Electrode Pad Setup Screen, FIG. 31, by a touch sensitive box.

[1013] e) The MP may prefer to configure his array of touch sensitive screens so that the Screen Menu is on display at all times.

[1014] There are various ways that newly called up screens can displace previous ones. These include:

[1015] a) having the previously used screen “move” one screen up, rightwards, or leftwards. At a point when live screen capacity is exceed, the overflow screen is no longer displayed (until and unless it is selected again);

[1016] b) always displaying certain fundamentally important screens such as Confirmations (FIG. 24), Main Defibrillation (FIG. 33) and Screen Menu (FIG. 43); leaving the remaining touch sensitive screens to be used as needed;

[1017] c) having successively used screens overlay each other. For example, selecting OTHER under Electrodes on the Main Defibrillation Screen (as was done during the sample cardiac arrest in Table 11), brings up the appropriate electrode setup screen (FIG. 31, for the five-electrode pad). This screen would be superimposed upon the Main Defibrillation Screen until the appropriate selections are made (the α and ε pads) after which the Five Electrode Pad Setup Screen would disappear and the Main Defibrillation Screen would reappear;

[1018] d) combinations of the approaches described in (a), (b) and (c).

[1019] Note that the number of screens available for viewing may be increased by: a) simply designing the MP console (FIG. 3) so that it contains more screens; or b) using screen-in-screen or split screen technology, allowing each physical screen to simultaneously show more than one menu or display.

4.5.2.2 Facilitated Lock Release in the Event of Failure of Handshake #1 or #2

[1020] As mentioned in Section 4.1.2.3.1, the third level of backup for a failed communication handshake or a failed data/commands handshake is during the enabler-MP link is for the PU to automatically enter Master Control State 2. This transfers control of defibrillation and pacing to the AED/P 128. Master Control State 2 also enables release of the mechanism which locks the PU to the SU. The actual release may be: a) fully automatic, whereby entry into Master Control State 2 directly causes lock release; b) enabler facilitated, in which a voice prompt tells the enabler a combination which is entered on a keyboard; or c) enabler facilitated, in which a voice prompt tells the enabler a combination which is used to open a mechanical combination lock.

4.5.3 Specific Issues During Phase Three

4.5.3.1 The MP Interface with Emergency Medical Services

[1021] At 0:50 during the sample arrest outlined in Table 11, the emergency medical team local to the victim is called by the central station. They may be called: a) directly by the MP; b) by a CS administrator, or other person working with the MP (so that MP's attention need not be diverted from dealing with the EN); or c) by computer. As shown in FIG. 27, the PU Deployment Screen, the MP may be provided with access to information about:

[1022] a) the hospital nearest the victim;

[1023] b) the emergency service (fire department, police or hospital based) nearest the victim;

[1024] c) estimated arrival times for the nearest emergency service; and

[1025] d) telephone numbers for contacting these emergency services.

4.5.3.2 MP Actions During Transport of PU to Victim

[1026] At 0:56, the enabler begins moving the PU to the victim's side. (For additional discussion and illustration of this event, see Section 5.4.1 and FIG. 17.) During this time, if it is established that EN and MP can hear each other well while EN is transporting the PU, MP may further discuss the situation with EN. During such discussion, MP would:

[1027] a) ask for and obtain additional description of the emergency;

[1028] b) ask for the victim's identification, if known (This would allow the MP to begin searching one or more databases for further information about the victim's past medical history, about a health care proxy (if any) and about advance directives (if any). In Table 11, the identification information is obtained later, i.e. during phase five);

[1029] c) tell EN exactly how the PU should be situated (i.e. with handles and screens facing upwards), when placed on the ground or on a stable, flat surface, very near to the VI;

[1030] d) give EN a preview, if time allows, of other tasks to be performed, upon arrival at the VI; and

[1031] e) reassure the EN—i.e. that MP is highly experienced, that MP will do all of the decision making, that MP will guide EN through a series of simple steps that require no prior medical training, and that an emergency medical team has been summoned.

[1032] At 1:42, immediately after EN puts down the PU near the VI, MP will reassess the quality of the audio link between himself and the EN, and make any adjustments necessary to optimize audibility at both ends. (For additional discussion and illustration of this event, see Section 5.4.2.2 and FIG. 18B.)

[1033] If necessary, MP may ask EN to use a headset, containing both microphone and earphone, contained in the tool-kit section of the PU. This would be especially useful in either a noisy environment, or if EN is hard of hearing. The headset could be wired directly into the PU or could have a wireless link to the PU.

4.5.3.3 MP Assessments and Actions, Upon Arrival of the PU at the Victim's Side

[1034] At 1:46, shortly after arrival of the MP at the VI, MP asks EN for an update on the VI. If the victim had regained consciousness during the time that EN had been in transit, then the next step would be for the MP to further assess the VI, either by direct observation (checking for victim motion or speech) or via the EN (who might, upon prompting by the MP, ask questions of the VI). Based on this further assessment, MP would decide whether there is a need to expose the victim's chest for application of one of the larger electrode pads. If it is anticipated that the likelihood of needing pacing or a defibrillation shock is substantial, then application of one of the electrode pads with this capability would be the next step. If, however, such therapy is not likely to be needed, the Mini-Pads 211, located on the fifth shelf from the top of the PU (see FIG. 7B) could be used as standard ECG leads, and be applied by the EN (under direction of the MP) to the arms and legs of the victim. This would provide the MP with an electrocardiographic tracing from which he could determine the victim's heart rate and rhythm. In the scenario of Table 11, in which the victim has had a cardiac arrest due to ventricular fibrillation, the victim did not (and could not have) regained consciousness; the EN thus informs the MP that the victim is unconscious.

[1035] At 1:54, after adjustment of the PU video camera, if the MP determines that the PU location is sub-optimal, e.g. too far from the victim, MP will inform EN of the need to reposition the PU.

[1036] At 1:56, the instruction in exposing the victim's chest includes telling the EN: a) the reason for exposing the chest; b) that there is a scissors in the tool-kit, which can be used, if necessary; and c) the extent of the area which needs to be bare, to accommodate the electrode pad(s). The MP may display instructional video materials on the PU screen 156 which illustrate the location of the scissors within the tool-kit (FIG. 7A) and the proper approach to clothing removal. When displaying instructional video materials, the MP would work from Video Control and Instruction Screen, FIG. 28 (discussed below).

[1037] Based on MP observations of the victim while EN is exposing the chest, MP decides which of the electrode pads contained in the tool-kit best suits the victim. In the current scenario electrode pad 204B is selected (at 2:03) which could be used on a male, or a female who did not have large breasts. This pad has five large defibrillating electrodes and seven small ECG electrodes. The choice of pad is based on MP judgment and experience.

[1038] At 2:15 and at 2:17 during the sample arrest, the MP assesses how well the pad has been applied to the victim's skin by observing (at 2:15) the display of impedance measurements for each electrode, and by observing (at 2:17) the multi-lead ECG signal. These are displayed in the central station on the Initial ECG Screen (FIG. 29, discussed below) and on the dedicated ECG screen 302 (FIG. 3). According to techniques known in the art the system would optimize the ECG signal; the MP would have the option of changing the system-selected parameters (e.g. the gain) or otherwise adjusting the signal. The MP might tell the enabler to press down over one or more sections of the pad if the MP observes high impedance readings or low amplitude ECG recordings corresponding to such an area.

4.5.3.4 Enabler Headset Handshake

[1039] The enabler may need to use a headset-microphone combination 168, contained in the tool-kit, if either he or the MP are not hearing each other well. If the headset-microphone is wireless, then its proper linkage to the PU may be confirmed by: a) a formal handshake routine analogous to the first three layers of the enabler-MP handshake (see Sections 4.1.2.3.1 through 4.1.2.3.3 and Table 7); or b) a much simpler audio handshake, analogous to layer three only, primarily intended to allow for the adjustment of gain controls on each end. The simpler handshake described in (b) would be the approach if the headset-microphone had a wire connection to the PU.

4.5.4 Specific Issues During Phase Four:

4.5.4.1 Wide Variety of MP Choices for Defibrillation and Pacing Parameters; Central Station Screens which Correspond to these Choices

[1040] The MP has access to a wide variety of treatment choices concerning the details of defibrillation and pacing; The choices selected during the sample arrest represent only a small fraction of the available options.

[1041] During the sample arrest, when defibrillation was necessary, the MP initially chose default values of shock parameters; When a second shock was necessary, the MP chose to alter the electrode pair through which the defibrillation energy was directed. Other MP options concerning defibrillation parameters include: a) changing defibrillation energy (FIG. 34, Defibrillation Energy Screen); b) changing shock synchronization (FIG. 35, Synchronization Screen), i.e. the precise timing of energy application; and c) changing the shape of the defibrillation pulse contour (FIG. 36, Pulse Contour Screen).

[1042] During the sample arrest, when pacing was necessary to treat a slow heart rhythm post-shock, the MP initially chose default values of pacing parameters; He later decreased the pacing rate. Other MP options concerning pacing parameters include: a) changing the pacer amplitude (FIG. 39, Pacer Output Screen); and b) changing the pacer pulse contour (FIG. 36, Pulse Contour Screen).

[1043] These central station screens, and others are discussed below in section 6.

4.5.4.2 MP Instructs Enabler in the Application of Blood Pressure and Blood Oxygen Saturation Devices

[1044] At 2:48 during the sample attest, once bradycardia pacing has commenced, the MP must determine the victim's blood pressure and blood oxygen saturation. The MP thus gives audio instructions to the enabler. The MP may also display instructional video materials on the PU screen 156 which illustrate the location of these two devices within the PU tool-kit (FIG. 7A) and the proper technique of their application to the victim. When displaying instructional video materials, the MP would work from Video Control and Instruction Screen, FIG. 28 (discussed below). The results of blood pressure and oxygen saturation determinations are displayed on screens 304 and 306 respectively, on the MP console in the central station (FIG. 3).

4.5.5 Specific Issues During Phase Five

4.5.5.1 Possible Performance of CPR During Phase Five

[1045] Once the blood pressure and blood oxygen saturation information is available, the MP will be able to make a determination as to the need, if any, for cardiopulmonary resuscitation. As was discussed above in section 4.3.2.2, CPR will need to be administered if, after the rhythm has been optimized, the blood pressure or oxygen saturation is, in the judgment of the MP, unacceptably low.

[1046] It is also possible that CPR would be needed during phase four. As was discussed above in section 4.3.2.2, this would be the case if either: a) ventricular fibrillation or tachycardia was present which was not responding to electrical shocks; or b) the MP determined that the administration of CPR before giving a shock was desirable.

4.5.5.2 Multiple Possible Types and Sources of Victim Related Information

[1047] Once the victim has been identified, the MP may obtain information about:

[1048] a) the victim's past medical history;

[1049] b) the victim's last or baseline electrocardiogram;

[1050] c) the victim's current medication names and doses;

[1051] d) the victim's allergies, drug and non-drug;

[1052] e) about an implanted pacemaker or defibrillator, including the manufacturer, model and programmed settings;

[1053] f) the names and telephone numbers of one or more of the victim's physicians;

[1054] g) the names and telephone numbers of hospitals or clinics where the victim may have been treated;

[1055] h) information about victim's next-of-kin; and

[1056] i) information about health care proxy and advance directive, if any, i.e. legal documents which may specify who and how health care decisions are to be made for this victim, if victim cannot participate in such decisions.

[1057] Such information may come from a number of databases or sources including:

[1058] a) a database maintained by the central station (which may be located (i) at the central station, (ii) at one or more off-site locations, or (iii) both);

[1059] b) the victim's physician(s);

[1060] c) hospitals or clinics where the victim had been treated;

[1061] d) private corporations or other business entities which may maintain such databases; and

[1062] e) government based data archives including Medicare, Medicaid, and other state and foreign sources.

[1063] f) a card or other item carried by the victim onto which medical information has been encoded, which may be decoded by apparatus within the PU.

[1064] The encoding, transmission, retrieval, display and storage of the aforementioned information would be carried out in accordance with all government regulations regarding privacy.

[1065] Although victim identification during the sample arrest occurs during phase five, it could occur as early as phase three or as late as phase six; or not at all.

4.5.5.3 Multiple Possible Means of Tracking Local Emergency Services

[1066] At 3:36 during the sample arrest, the MP informs the enabler of the estimated time of arrival of the local Emergency Medical Team. In a preferred embodiment of the invention, the Portable Unit Deployment Screen (FIG. 27) displays this estimate. Such information may be obtained:

[1067] a) from an EMT estimate which is inputted directly to the central station;

[1068] b) from a verbal estimate supplied by the EMT;

[1069] c) from (i) global positioning (GPS) equipment within an EMT vehicle, (ii) a computer program which estimates travel time (such as Microsoft® Expedia™ Trip Planner 98), and (iii) a computer on which this program runs; whereby GPS-derived data regarding EMT location is inputted into the computer which is running the travel time program, and the computer supplies the central station console with estimated arrival time information, which is displayed on the Portable Unit Deployment Screen (FIG. 27); or

[1070] d) from a non-automated version of (c), in which the location of the EMT is manually entered into the aforementioned travel time program.

[1071] Using any of these methods, the MP may track the location of more than one EMT and thereby facilitate the deployment of such teams by:

[1072] a) informing an emergency medical team of the location of another team or team(s);

[1073] b) directing the team with the shortest estimated arrival time to proceed to the scene of the emergency;

[1074] c) directing the most well equipped team to the scene of the medical emergency;

[1075] d) using information about the location of a team and how well equipped it is to select the most appropriate team or team(s).

4.5.6 Phase Six: Specific Issues During Phase Six

4.5.6.1 Analogous Aspects of the Enabler-MP Link During Phase Two, and the EMT-MP Link During Phase Six

[1076] As was discussed in 4.1.6.2, the four handshakes which constitute the EMT-MP link are analogous to the four handshakes which constitute the enabler-MP link (see also Tables 7 and 9, above).

[1077] Another analogous feature resides in the third level of backup, in the event of failure of a handshake in layer #1 or #2. In each of the two links, the system is designed to allow a “probably appropriate” user to have access to the PU; i.e. it gives the “benefit of the doubt” to the person desiring access. In each of the two links, the primary mode of operation is for the MP to approve the release of the unit, either: a) physically, with the PU to be removed from the SU, following the enabler-MP link; or b) electrically, to be controlled by the EMT, following the EMT-MP link. The secondary mode is to allow release of the unit without MP approval, as described above and below, in the event of handshake failure.

[1078] In the event of a failure of either of the first two handshakes between enabler and MP, the enabler can gain access to the PU without the MP having to release the unit. In this case, the PU (functioning in Master Control State 2, independent from the CS) informs the enabler of the combination to a lock, mechanical or electrical, which releases the PU from the SU; In an alternative embodiment, the PU could be automatically released in the event of handshake failure in the first two layers of the enabler-MP link.

[1079] Similarly, in the case of the EMT-MP link, as was discussed above in Section 4.1.6.2.1, a failure of either of the first two handshakes lets the EMT bypass the usual MP-based password approval; The PU itself will accept a pre-programmed EMT password, without MP approval, in the event of an unsuccessful communication or data/command handshake.

4.5.6.2 Timing of EMT Arrival

[1080] During the sample arrest, the EMT is called at 0:50 and arrives at 7:25. This constitutes an elapsed time of six minutes and thirty five seconds, which is a reasonable estimate by large city standards

[1081] One way to view the effectiveness of the invention is to consider how much time was saved by instituting life-saving therapy (i.e. defibrillation) before the EMT arrived. It is possible to estimate a lower boundary for this parameter.

4.5.6.2.1 Time Saved by Using the Invention: Estimation of the Earliest Possible Defibrillation by EMT, Without the Invention

[1082] A number of assumptions must be made to perform this estimation:

[1083] a) Assume that EMT had been called at the moment of button press, i.e. 0:31 (see Table 11). This assumes that the amount of time required to press the button is the amount of time required to call 9-1-1.

[1084] b) Assume that six seconds are needed to describe the event to the EMT dispatcher. This is the same estimate used for the sample arrest. This puts their dispatch at 0:37.

[1085] c) Assume (as was assumed during the sample arrest, above) that six minutes and thirty five seconds is the time from EMT dispatch until EMT arrival. This puts their arrival time at 7:12 after enabler noticed the victim

[1086] d) Assume that from the moment of EMT arrival until they assess the victim, remove or cut the victim's upper garment, hook up their defibrillator, diagnose VF, charge their defibrillator and finally shock the VF, is 30 seconds, i.e. an extremely rapid performance. This puts the time of first shock at 7:42 after enabler noticed the victim.

[1087] e) Assume that the first shock was effective. The only reason to make such an assumption (aside from trying to come up with the lowest possible estimate of the time to EMT termination of VF) would be if the EMT did a substantially better job of attaching and orienting the electrode pad than did the MP/enabler. In reality, it is likely that MP/enabler shocks will be more successful than EMT shocks, because the MP/enabler shocks will be administered much sooner than the EMT shock. The time of the shock when the invention is not used is 7:42; the time (of the [definitive] second shock) when the invention is used is 2:40 (Table 11).

[1088] Working with the aforementioned five assumptions, definitive therapy comes nearly five minutes sooner (2:40 vs. 7:42), using the invention. It is estimated that cardiac arrest mortality increases by roughly ten percent per elapsed minute without therapy. Therefore, using these extremely optimistic estimates for EMT performance, the invention would be expected to cause an approximately 50% reduction in the mortality from a cardiac arrest.

4.5.6.2.2 More Realistic Estimates for EMT Defibrillation

[1089] Two issues make the aforementioned estimate of EMT performance (without the invention) especially optimistic:

[1090] a) Assumption (e). Because ventricular fibrillation is assumed to have been going on for more than seven minutes before EMT arrival (without the invention), there is a good chance that the first shock will not be successful. Multiple shocks might be required. A period of CPR might need to precede one or more of the shocks. And, it is possible that a successful shock at this late time might not occur until after intravenous medication has been administered. If this is the case, even more time is lost.

[1091] b) In the current analysis, it has been assumed that the endpoint for resuscitation is the time of termination of VF. If, instead, the endpoint of the resuscitation process is assumed to be the moment when a survivable blood pressure is restored, then there may be an even greater disparity between the resuscitation time without the invention, compared to that with the invention. The prolonged time of abnormal heart rhythm (without the invention) is again the reason. During the minutes when the heart is in VF, unless CPR is performed, the blood pH falls, the level of potassium in the blood rises, and the heart muscle cells suffer from oxygen deprivation and accumulation of toxic metabolites. The result is that even when VF is terminated, the heart's mechanical performance is initially poor. The longer the period of VF without any therapy, the greater the time until good mechanical performance can be restored, if ever. Thus, the five minute delay until the definitive shock is administered (when the invention is not used), causes additional delay in the restoration of proper cardiac mechanical performance.

4.5.7 Specific Issues During Phase Seven

4.5.7.1 Overview of Phase Seven: Two Sequences of Events

[1092] Two sequences of events occur during phase seven of the sample cardiac arrest. The first involves transfer of control to the EMT. The second involves replacement of the PU.

4.5.7.1.1 Analogous Aspects of Phase Seven and Phase Three

[1093] The first and most important sequence of events during phase seven, parallels events during phase three (in which the enabler obtains the PU, and is guided by the MP in its setup), and involves EMT obtaining control of the PU, with MP guidance of the EMT. This sequence of events includes:

[1094] a) release of the PU to the EMT (see Section 4.1.7.1);

[1095] b) presenting the details of the event with the EMT (see Section 4.1.7.2);

[1096] c) instructing the EMT in the operation of the PU, when such instruction is needed (see Sections 4.1.7.2 and 4.1.7.4.1); and

[1097] d) attaching a new PU to the victim, (occurs only when EMT brings a new PU and it is to be attached to the victim; see Section 4.5.7.2.2).

[1098] The second sequence of events during phase seven is analogous to a time-reversed version of phase three events, and involves attaching a PU to the SU. Such phase seven events include:

[1099] a) replacing the non-disposables in the PU tool-kit, when necessary (see Section 4.5.7.3.4);

[1100] b) retracting the video boom and the PU antenna, when necessary (see Section 4.5.7.3.5);

[1101] c) transporting a PU back to the SU (see Sections 4.5.7.2.1 and 4.5.7.3.6); and

[1102] d) attaching this PU to the SU (see Section 4.5.7.4.3).

“When necessary,” above, pertains only to scenarios in which the old PU is returned to the SU.

[1103] The phase three events which are paralleled by the aforementioned phase seven events are discussed above in Sections 4.1.3.1 and 4.5.3.2; and are listed in the phase three portion of Table 11.

4.5.7.1.2 Two vs. One Portable Unit at the Arrest Scene

[1104] There is complexity in describing PU deployment because: a) the EMT may or may not bring along another PU; and b) in each of these two situations, the old PU may or may not be returned to the SU. This results in two independent choices, each with two possible outcomes; the result is four possible options, described below and in Table 12.

[1105]

TABLE 12
Deployment of the Old PU After EMT Arrival
Option	Section	Old PU To:	New PU To:	Housekeeping
1	4.5.7.2.1	Victim	SU	Not Required
2	4.5.7.2.2	SU	Victim	Required
3	4.5.7.7.1	SU	No New PU	Required
4	4.5.7.7.2	Victim	No New PU	Not Required

[1106] If the EMT brings a replacement PU, there are two ways of deploying the old and the new portable units, hereinafter referred to as “option one” (old PU remains attached to victim; described in Section 4.5.7.2.1) and “option two” (old PU returned to SU; described in Section 4.5.7.2.2). These two options are further discussed below in Sections 4.5.7.3 through 4.5.7.6, and 4.5.7.8.2.

[1107] If the EMT does not bring a replacement PU there are two ways of deploying the old PU, hereinafter referred to as “option three” (old PU is returned to SU; described in Section 4.5.7.7.1) and “option four” (old PU remains attached to victim and is transported to hospital; described in Section 4.5.7.7.2). These latter two options are further discussed below in Sections 4.5.7.3, 4.5.7.4, 4.5.7.5.1 and 4.5.7.8.2.

4.5.7.2 Two Portable Units Available: New Versus Old PU as the Replacement Unit

[1108] In a preferred embodiment of the invention, the PU, in between events, is detachably mounted on a stationary unit which is permanently mounted on a wall at approximately eye level as shown in FIG. 2A. Before the enabler and EMT leave the scene of the arrest, it is therefore desirable that one of them attaches one of the portable units to the SU. The other PU is transported to the hospital, attached to the victim.

4.5.7.2.1 Option One: Old PU Remains Attached to the Victim; New PU to be Attached to the Stationary Unit; Transportation of the New PU to the SU

[1109] This is the scenario which is assumed to occur during the sample cardiac arrest, referred to in Section 4.1.6. (The scenario in 4.1.6.1, choice (b), also entails leaving the old PU attached to the victim.) It is the procedurally simpler than the scenario described immediately below (Section 4.5.7.2.2) in which the old PU is left behind, and the new PU is attached to the victim.

[1110] Unless otherwise specified, the present remarks refer to embodiments of the invention which have a stationary unit.

[1111] The current scenario (new PU left at the emergency scene) requires:

[1112] a) that the EMT brings another PU to the emergency scene;

[1113] b) that during a future emergency, the MP can match the new PU serial or identification number, with the PU location (This matching process is hereinafter referred to as “PU localization.”);

[1114] c) that the new PU is transported to the SU; and

[1115] d) that the new PU becomes physically attached to the SU (discussed in Section 4.5.7.4, below).

[1116] There are a variety of ways that PU localization may be accomplished:

[1117] a) The EMT may simply read the serial number of the new PU to the MP, who would enter it into the central station computer.

[1118] b) The EMT may press the emergency button on the new PU.

[1119] The new PU would then transmit its serial number to the MP who could enter it into the central station computer. Various means are available to let the MP know that the button press on the new PU is intended to indicate localization at the same site as the old PU, and does not constitute a different emergency.

[1120] c) The new PU may be programmed to transmit its identification information when it gets attached to the SU (see below), with the SU supplying the location identifier.

[1121] d) In a preferred embodiment of the invention, a global positioning system within the new PU would notify the CS of its location. This notification may be automatic or initiated by button press, and would optimally occur shortly after EMT arrival.

[1122] As indicated above, the new PU must be transported to the SU, to prepare the site for a future emergency. If enabler is the person transporting the new unit, he should know the SU location. If someone other than enabler is transporting the unit, either the MP or the enabler may inform him of the SU location.

4.5.7.2.2 Option Two: New PU is Attached to the Victim; Old PU to be Reattached to the Stationary Unit

[1123] This is the scenario which is referred to in Section 4.1.6.1, choices (a) and (c).

[1124] This scenario (old PU left behind) requires:

[1125] a) that the EMT brings another PU (the “new PU”) to the emergency scene;

[1126] b) that the EMT presses the emergency button on the new PU and goes through an abbreviated handshake routine to link the new PU with the CS;

[1127] c) that the old PU be detached from the victim;

[1128] d) that the new PU be attached to the victim;

[1129] e) that there be an abbreviated handshake routine to confirm the link between the new PU and the victim;

[1130] f) that certain “housekeeping” functions be performed to make the old PU ready for future re-use (discussed in Section 4.5.7.3, below);

[1131] g) that the old PU is transported to the SU; and

[1132] h) that the old PU becomes physically reattached to the SU (discussed in Section 4.5.7.4, below).

[1133] The handshake which follows the button press to link the new PU to the CS is conceptually similar to the enabler-MP link described in Section 4.1.2, but simpler. The reasons for the simplification are: a) AED/P backup is not needed; b) other backups are simpler as well, since the EMT and the MP are already in communication via the old PU; and c) the fourth layer of handshake, the informational handshake, is markedly simplified, compared to its counterpart during the enabler-MP handshake (when the enabler described the emergency to the MP); the only information that the EMT needs to give is the serial or identification number of the new PU, if it was not transmitted automatically at the time of new PU button press.

[1134] The universal connectors, discussed below, allow quick and easy detachment of an electrode pad from the PU, and reattachment of another electrode pad to the PU. In the current scenario, electrode pad 204B (five large defibrillating electrodes, seven small ECG electrodes; FIG. 5B) was used). This pad utilizes female universal connector “UC” 218A which connects to male UC 220A of the PU (FIG. 7B). To switch portable units, the EMT would:

[1135] a) disconnect the female and male universal connectors 218A and 220A on the new PU;

[1136] b) disconnect the female and male universal connectors 218A and 220A on the old PU (thereby briefly detaching the victim from the PU and leaving him briefly unmonitored);

[1137] c) attach the female UC 218A which terminates the cable extending from the electrode pad attached to the victim, to the male UC 220A which terminates the cable extending from the tool-kit (FIG. 7B) of the new PU, thereby re-establishing victim monitoring; and

[1138] d) attach the female UC 218A which terminates the cable extending from the unused electrode pad, to the male UC 220A which terminates the cable extending from the tool-kit of the old PU, thereby making the old PU ready for re-use.

[1139] The EMT and/or MP confirm that the victim's electrode pad is properly attached to the new PU with a handshake which is analogous to but simpler than the third layer of the victim-MP link (see Section 4.1.3.2.1 above). Simplification results from the fact that the electrode pad was already shown to be functional and properly placed during its earlier use. The handshake is performed by: a) observing the electrocardiogram tracing on the new PU; and b) going to the Initial ECG Screen (FIG. 29) and confirming that the impedance values (which assess the quality of the pad-victim interface) are in proper range. Troubleshooting for this activity involves the backups presented above in Table 9 (Section 4.1.3.2.1).

[1140] The brief period of absence of victim monitoring is a disadvantage of this approach, compared with the approach described in Section 4.5.7.2.1, in which the old PU is never detached from the victim. However, a ‘Y’ connector arrangement, in which the some or all of the electrodes in the pad are in electrical continuity with a second cable which terminates in a second female connector, could prevent this problem. This second cable would be attached to the new PU before the first cable would be detached from the old PU; Accordingly, there would never be a time when the victim was not attached to at least one of the portable units.

[1141] The process of preparing the old PU for reuse and of reattaching it to the SU is described below (see Sections 4.5.7.3 and 4.5.7.4).

4.5.7.3 Housekeeping Activities Before Returning the Old PU to the SU; Transportation of the Old PU to the SU

[1142] If the old PU is to be left at the scene of the emergency (as occurs in options two and three), the ideal approach would be to do as many things as possible to restore it to a ready-to-use condition. Such restoration activities are herein referred to as housekeeping activities. The electrode pad is generally not reusable; the same may be true of the oximetry sensor. In a preferred embodiment of the invention, extra pads and oximetry sensors (if disposable) are stored in the miscellaneous section 177 of the tool-kit of the PU (FIG. 7A) and can be used to replace these disposable items (see Section 4.5.7.3.3). Used, non-disposable items must be returned to the tool-kit (see Section 4.5.7.3.4).

4.5.7.3.1 MP Role During Housekeeping

[1143] The MP role in housekeeping activities involves:

[1144] a) confirming proper electrode pad replacement;

[1145] b) guiding on-site person(s) in the performance of certain activities;

[1146] c) inspecting the PU during or after these activities, to confirm their proper performance; and

[1147] d) retracting the video boom, once inspection is complete (see Section 4.5.7.3.5).

[1148] e) making sure that after the event is over, a replacement PU is properly positioned, functioning and supplied.

4.5.7.3.2 Choice of Individual to Perform the Housekeeping Activities

[1149] The choices for who performs the on-site housekeeping activities include:

[1150] a) the EMT;

[1151] b) the enabler;

[1152] c) another bystander at the scene of the emergency, other than the person who has functioned as the enabler; and

[1153] d) a person (arriving after the medical emergency) from, or related to the same organization that includes the central station and/or the medical professional (see section 4.6).

[1154] e) combinations of the above.

[1155] We shall assume, in the sections that follow, that the enabler performs this function. The MP would make sure that at least one of these persons is selected, and that the person or persons responsible for these activities: a) is aware of their responsibilities; and b) carries them out.
4.5.7.3.3 Electrode Pad Replacement; Oximetry Sensor Replacement

[1156] In the case of option two, when a new PU is substituted for the old one, electrode pad replacement should have already been performed (see four step process in Section 4.5.7.2.2), using a replacement pad from the tool-kit of the new PU. If an EMT who is under time pressure does not perform the fourth step listed in Section 4.5.7.2.2 (i.e. replacing the pad on the old PU), the enabler (or person performing the housekeeping functions) would do it at this point. (The same replacement process would occur in the case of option three [EMT does not bring a PU and leaves the PU at the arrest scene], see Section 4.5.7.7.1.) In order to accomplish this task, the enabler must: a) disconnect the used pad; b) remove a new pad from the tool-kit; and c) connect the new pad.

[1157] The old pad is removed by disconnecting the female universal connector 218A (to which the pad is attached) from the male UC 220A. A new pad, labeled to indicate that it is the same one which has been used, is removed from the tool-kit and connected to universal connector 220A.

[1158] The MP has two ways of knowing that this procedure was performed properly: First, the female UC (the UC which comes from the electrode pad) has certain pairs of pins which are electrically common (see below and see FIGS. 56B-56F). The UC for each of the different types of pad has a different pair of electrically common pins. Therefore, by observing the impedance readings for the circuits involving the previously used pad, it is possible for the MP to know: a) that the old pad was disconnected; b) that the new pad was connected; and c) that the correct pad was connected. Furthermore, in a preferred embodiment of the invention, the MP can know that the enabler did not simply reconnect the old pad, as follows: The electrical continuity created by the conductive strip 266 within the pad backing 260 (see Section 3.2 and FIG. 5E) distinguishes an unused pad (with intact backing and conductive strip) from one with the backing removed.

[1159] Second, the MP can use the video camera of the old PU to observe enabler's performance. This may be useful if enabler is unsure about which pad to select, or how physically to connect or disconnect the UCs. The MP can also use the video camera to make sure: a) that the enabler gently pushes the pair of UCs 218A and 220A and ribbon cables 212A and 222 onto the appropriate shelf (166A) in the upper portion of the tool-kit; and b) that the enabler then places the newly attached pad on the appropriate shelf in front of the UCs and cables. However, although visual confirmation is valuable, the ultimate verification of a properly completed pad replacement is electrical, as described above.

[1160] The oximetry sensor 174 would also be replaced at this time, if it is the disposable type, by simply disconnecting the old one (if not already done by the EMT) and replacing it with a spare from the tool-kit.

4.5.7.3.4 Replacement of Non-Disposable Items

[1161] The MP would make sure that the enabler places the blood pressure cuff 172 and scissors 170 in the appropriate compartments of the PU tool-kit (FIG. 7A). If the oximetry sensor 174 is the non-disposable type, it too would be returned to the tool-kit at this time.

[1162] If either the wireless headset 168 or the telephone cable 176 has been used, they now need to be replaced. The MP can re-attempt communication by means which do not require the headset (e.g. via PU speakers 146 and PU microphone 148, or via PU handset 150) or the telephone cable; But the MP must first tell enabler the remainder of the replacement plan, in case communication is immediately lost or later interrupted, once these items 168 and 176 are returned to the tool-kit. The remainder of the plan involves: a) closing the tool-kit door; b) transporting the PU back to the SU; and c) attaching the PU to the SU (as described below in 4.5.7.4)

[1163] MP confirmation that these steps have taken place is either based on enabler's statement to this effect, or by observation via video camera. If communication is terminated (because it was based on the headset and/or the telephone cable) before all enabler tasks are confirmed, they can be confirmed once communication is re-established, after the PU is returned to the SU.

4.5.7.3.5 Video Boom and Antenna Retraction Prior to Moving the PU

[1164] Prior to moving the PU, the MP must retract the video boom 112 so that the video camera 154, if it has been deployed, is returned to a position inside of the PU. This protects it from damage during the move. This can be performed once the inspection process is complete.

[1165] Prior to enabler's moving the PU, the MP may instruct the enabler to lower the PU antenna 162, if it has been raised. MP may inform the enabler that if communication disruption occurs once the antenna is lowered, then enabler's choices are to: a) raise the antenna and press the emergency button; or, b) return the old PU to the vicinity of the SU, and then attempt to re-establish communication, by button press, with or without antenna extension. In a preferred embodiment of the invention, antenna movement is directly controlled by the MP, by mechanical means as are known in the art. If MP wishes to avoid the potential disruption in communication that might occur as a result of antenna lowering, he may allow the PU to be transported without retracting the antenna.

4.5.7.3.6 Transportation of the Old PU to the SU

[1166] If the old PU is being returned to the SU, the MP, as soon as the video boom is retracted, informs the enabler that he may return the PU. If enabler is the person returning the unit, he should know where it came from. If someone other than enabler is returning the unit, either the MP or the enabler may inform him of the SU location.

4.5.7.4 Attachment of the PU to the SU

[1167] Such attachment occurs during option one (Section 4.5.7.2.1), option two (Section 4.5.7.2.2) and option three (Section 4.5.7.7.1).

4.5.7.4.1 Who Performs the Attachment?

[1168] The choices for who attaches the new or old PU to the SU are identical to those for the performance of the housekeeping functions, discussed above in Section 4.5.7.3.1. Again, we shall assume that the enabler performs this function.

4.5.7.4.2 Mechanical Issues in the Attachment Process

[1169] FIG. 9 shows that the SU has a shelf in its lower portion, which supports the PU. Replacing the PU requires sliding it across the shelf, from the front of the shelf to back of the shelf; so that the power connector 186 on the PU (FIG. 8) engages its counterpart, power connector 192 on the SU. In similar fashion, telemetry connector 188 on the PU engages its counterpart 190 on the SU. Meanwhile, the locking projection 194, extending from the SU will engage the PU receptacle and electromagnetic lock within the SU.

[1170] A variety of mechanical mechanisms (not shown in FIG. 8 or 9) may facilitate the attachment procedure:

[1171] a) The SU shelf may include small wheels or cylindrical rollers on its surface, to facilitate sliding the PU back toward the vertical part of the SU.

[1172] b) Alternatively (or, in addition), the PU may also include such small wheels or rollers on its under-surface. (The under-surface of the PU is defined as the surface opposite the that which contains the handle shown in FIG. 8.)

[1173] c) Locator pins may project from the SU and enter receptacles in the PU to help guide the PU as the enabler pushes it into place.

[1174] d) A narrow “wall” at each edge of the SU shelf would help guide the PU.

[1175] e) Grooves in the SU shelf with matching projections on the under-surface of the PU, or the inverse arrangement with grooves in the PU under-surface and matching projections on the SU shelf, would help guide the PU.

[1176] The MP may facilitate the attachment procedure by informing the enabler of the mechanical guides which help align and position the PU as it returned to the SU.

4.5.7.4.3 Endpoint for PU-SU Attachment

[1177] The goal for this step is to have the enabler return the PU to the position in which it is attached to the SU, and in which it is designed to remain, in between deployments: hereinafter referred to as the “home position.” In the home position:

[1178] a) each of the sensor switches 178 has its central dowel depressed by an appropriate amount;

[1179] b) each of the PU feet 180 is resting in its proper position with respect to the SU shelf;

[1180] c) the PU telemetry connector 188 properly engages its counterpart, the SU telemetry connector 190;

[1181] d) the PU power connector 186 properly engages its counterpart, the SU power connector 192; and

[1182] e) the SU locking projection 194 properly enters and engages PU receptacle and electromagnetic lock 182.

[1183] The MP may gauge the progress and adequacy of the PU-SU attachment process by monitoring a number indicators available to him: These indicators include the following:

[1184] a) The PU sensors switches 178 (FIG. 8, Section 2.3) will provide position and orientation information as the PU nears its home position. As the PU nears the home position, the central dowel within the sensor switch is depressed, providing position information. Proper orientation of the PU is deduced when multiple sensor switches show identical degrees of depression (to within the limits of measurement) simultaneously. The greater the number of sensor switch positions, and the greater the number of sensor switches, the more detailed is the position and alignment information available to the MP. Furthermore, when three or more sensor switches are present, their placement in any non-linear pattern will give the MP information about misalignment of “pitch” or “yaw.”

[1185] b) The MP will know when the PU telemetry connector 188 (FIG. 8) properly engages the SU telemetry connector 190 (FIG. 9) as the home position is approached.

[1186] c) In the home position, the SU locking projection 194 (FIG. 9) engages the electromagnetic locking mechanism 182 within PU. Sensors within the locking mechanism can inform the MP of proper engagement.

[1187] d) Other sensors (not shown): (i) mechanical, (ii) photoelectric, (iii) laser or (iv) continuity, may be positioned in the SU shelf 108, the PU bottom and the PU back. They would give the MP additional PU position information, as the PU slides toward the home position.

[1188] e) A grid, cross, dot, mark, pattern, picture, or mirror could be placed on a wall opposite the PU (i.e. the wall which the screen side of the PU faces). Sighting through the video camera would allow for the detection of misalignament, though this could only occur once the enabler has moved out of the way. The MP could also use a combination of these indicators.

[1189] The MP would inform the enabler, if MP has evidence of either misalignment or insufficient advancement of the PU, and would tell enabler of suggested corrective action.

[1190] It would also be possible to guide the enabler automatically (e.g. with voice prompts) without MP involvement. This approach would be useful: a) in the event of communications failure (see Section 4.5.7.5, below); or b) if (i) a new PU was being mounted and (ii) the PU localization process (see Section 4.5.7.2.1) had not yet been performed.

[1191] There are a variety of approaches to informing the enabler as to when the PU has been properly and adequately advanced, and is correctly situated in the home position:

[1192] a) The MP may tell the enabler that the PU is properly positioned.

[1193] b) An audible mechanical click may be heard when the lock engages.

[1194] c) The PU may emit a tone or a voice prompt indicating proper attachment.

[1195] d) One or both of the screens 156 may flash and/or provide a text message indicating proper attachment.

[1196] e) Resistance to further PU motion (either towards or away from the back wall of the SU) could serve as an indicator.

4.5.7.4.4 Checking the PU Post-Attachment

[1197] Attaching the PU to the SU initiates a diagnostic checking routine that is described below (see Section 4.6.2). When this occurs, the PU enters Master Control State 4 (see table 1 and Section 1.3.1.2) The check is performed whether the attached PU is an old or a new one. Electrical functioning within the PU and the SU, as well as the integrity of the PU-SU connections are assessed.

[1198] Using the video camera 154, the MP may also perform a visual check which includes: a) an inspection of the PU and SU; and b) an assessment of the functioning of the PU screens 156 (see Section 4.6.2)

4.5.7.5 Choices in the Event of Communications Failure During Phase Seven;

[1199] Once the EMT has arrived and assumed control of the PU, a communications failure with the central station would not be nearly as momentous as one prior to EMT arrival.

[1200] If a break in communications occurs, the MP, immediately aware of it, makes efforts to restore the link using techniques referred to above, in Section 4.1.2, and below. The PU would: a) notify the EMT (by voice prompt, screen message or text printout), who would have multiple communication possibilities (see Section 4.5.7.5.1, below); b) present EMT with an audio, video or printed summary of the arrest (containing the information stored in the PU, i.e. the first six of the thirteen items listed above in Section 4.1.7.2), if MP had not completed this task before communications interruption; and c) present EMT with an audio, video or printed version of PU operating instructions, if the MP had not completed this task before communications interruption.

4.5.7.5.1 EMT Communications Choices Using Only One Portable Unit

[1201] If he becomes aware of a communications failure between the PU and the CS, the EMT has the following choices:

[1202] a) The EMT may make no active effort to restore communication, allowing MP to perform this function.

[1203] b) The EMT may access a simplified version of the Communications and Triage Screen (FIG. 25) from the truncated Screen Menu, via PU screen 156. This would allow the EMT to chose “GO TO AED/P”. Such a choice could be useful if the EMT is busy doing other activities and not able to attend to the ECG monitor. The EMT could, alternatively select a monitoring function, which (i) sounds an audible alarm if a heart rate or rhythm abnormality is detected by the PU, but (ii) does not render treatment, allowing EMT performance of the latter. Yet another EMT alternative via the modified Communications and Triage Screen is a hybrid of the two previously mentioned approaches. That is, the AED/P could be set up to (i) sound an audible alarm if a heart rate or rhythm abnormality is detected by the PU, and (ii) delay treatment for a programmable number of seconds, such that the AED/P gives the EMT a certain amount of time to render treatment, before the AED/P does.

[1204] c) The EMT may attempt to restore communications by plugging telephone cable 176 (see Section 2.2 and FIG. 7A), extending from the PU attached to the victim, into a nearby telephone jack of the public telephone network, if available, at the arrest scene. The EMT would then attempt to re-establish communication with the MP via the public telephone network. This attempt would be initiated by simply pressing emergency button 106 on the portable unit (FIG. 6A).

[1205] d) The EMT may attempt to restore communications by plugging telephone cable 176, extending from the PU attached to the victim, into the female telephone jack 155 of the stationary unit, if he is within reach of it. The EMT would then attempt to re-establish communications with the MP via the SU by pressing emergency button 106 on the PU.

[1206] e) The EMT may manipulate PU antenna 162 by either (i) extending or retracting it and/or (ii) changing its orientation; followed in either case by pressing emergency button 106 on the PU.

4.5.7.5.2 EMT Communications Choices Using a Second Portable Unit

[1207] The EMT, if he has brought a PU to the arrest scene, may attempt to contact the MP via the PU not currently attached to the victim, hereinafter referred to as “PU-2” (whether it be the new or the old one). Certain actions by the EMT may render the second PU more likely to communicate with the MP, than is the PU which is attached to the victim, hereinafter referred to as “PU-1.” These actions include:

[1208] a) moving PU-2 outside or nearer to the outside of a building;

[1209] b) moving PU-2 so that it is within reach of a telephone jack which allows connection to the public telephone network;

[1210] c) moving PU-2 so that it is located in between the stationary unit and PU-1; and

[1211] d) moving PU-2 to any other location.

[1212] There are two possible approaches to using PU-2: a) using PU-2 as the only PU; and b) using both PU-1 and PU-2 in tandem.

4.5.7.5.2.1 Choice in which PU-2 is the Only PU which Communicates with the Central Station

[1213] The rationale for using PU-2 as the only PU, instead of PU-1 is because PU-2 might be capable of communication with the CS even though PU-1 is not. Possible reasons for non-equivalent performance of the PUs are: a) PU-2 being a different model portable unit (though nevertheless an embodiment of the invention) with a more robust communications system; b) PU-2 being in a different position, allowing for greater signal strength (in either or both directions) than PU-1; or c) a malfunction in PU-1.

[1214] If PU-2 is successful in communicating with the central station, methods of using it include: a) simply using it as a communication device between MP and EMT, without PU-2 having a direct link to the victim; b) connecting PU-2 to the victim's electrode pad by switching the universal connectors (analogous to the procedure described in Section 4.5.7.2.2); or c) connecting PU-2 to PU-1 by extending the telephone cable 176 coming from PU-1, to PU-2, resulting in tandem operation of the PUs. (There are also other possible means of linking PU-2 to PU-1, see below.)

4.5.7.5.2.2 Choices in which Both PU-1 and PU-2 are Used in Tandem; Even More Elaborate Links

[1215] There are multiple possible configurations using both PUs in tandem operation. The features of the link that may be varied include:

[1216] a) The first segment of the link, i.e. that from PU-1 to PU-2, may be wireless or wire. The terms “wireless” and “wire” have been defined above, in Section 4.1.2.4. In a preferred embodiment of the invention, the wire may be cable 176 coming from PU-1 which may be plugged into female jack 153 of PU-2.

[1217] b) The second segment of the link, i.e. that from PU 2 towards the central station, may connect PU-2 with either (i) the stationary unit or (ii) the central station.

[1218] c) If the second segment of the link is between PU-2 and the SU, it may be wireless or wire. If it is a wire link, it may be achieved by plugging telephone cable 176, extending from the PU-2, into the female telephone jack 155 of the stationary unit.

[1219] d) If the second segment of the link is between PU-2 and the central station, it may be wireless or wire. If it is a wire link, it may be achieved by plugging telephone cable 176, extending from PU-2, into a female telephone jack of the public telephone network.

[1220] Table 13, below, lists different possible combinations of the aforementioned first segment and second segment choices.

[1221]

TABLE 13
Communication Choices Using the Second PU as a Relay
	Segment #1	Segment #2
Choice	PU-1 to PU-2	PU-2 to SU	PU-2 to CS
1A	Wireless		Wireless
1B	Wireless	Wireless
2A	Wireless		Wire to TELCO
2B	Wireless	Wire to SU
3A	Wire		Wireless
3B	Wire	Wireless
4A	Wire		Wire to TELCO
4B	Wire	Wire to SU

[1222] Even more elaborate links involving larger numbers of PUs in tandem are possible.

[1223] Replacement of a PU at the SU is more complex when the link between the MP and the EMT or victim consists of two PUs. If a third PU is available, it may be attached to the SU. If not there may be a period without communication between the MP and the EMT or victim, during which time one of the PUs is moved to the SU and attached to it (as described in Section 4.5.7.4, above).

4.5.7.6. Possible Need for Two Nearly Simultaneous MP Conversations During Phase Seven

[1224] During the first four phases of the sample arrest, there are a number of times when the MP may be called upon to perform multiple tasks simultaneously (see Section 4.4.6). During these phases, however, there is virtually no instance when the MP must speak to two individuals simultaneously. (Even when MP calls the emergency medical team local to the victim, MP need not interrupt his conversation with the enabler [see Section 4.5.3.1].)

[1225] Since phase seven involves both MP guidance of the EMT and MP guidance of the person replacing the PU, it is possible that, under circumstances when two PUs are present at the arrest scene, the MP would be called upon to conduct separate but simultaneous conversations with each of the EMT and the enabler. However, this need for coincidental action is expected to be easily remediable since:

[1226] a) It is always possible to delay PU housekeeping and replacement;

[1227] b) PU housekeeping and replacement consists of multiple sub-tasks; therefore, the MP could interweave his supervision of one or more of these sub-tasks with his supervision of the EMT;

[1228] c) The EMT is expected to be capable of a certain substantial level of expertise and competence so that MP should be able to break away from conversation with the EMT for brief periods of time; and

[1229] d) The MP has the ability to assign excess workload immediately by accessing the Master Triage Screen (FIG. 42) from the Screen Menu (FIG. 43). The Master Triage Screen (discussed below) allows the MP to observe the activity of other MPs and hand off work to one or more of them, as needed.

4.5.7.7 The Circumstance in which EMT Does Not Bring a Replacement PU

[1230] If the EMT does not bring a second PU, then either: a) at some point prior to leaving the scene of the arrest, he must detach the PU from the victim (option three); or b) the PU remains attached to the victim and both are transported to the hospital (option four).

4.5.7.7.1 Option Three: Sole PU Remains at the Arrest Scene

[1231] If EMT is to leave the PU at the arrest scene, the MP requests that either the enabler or the EMT perform the housekeeping functions discussed in Section 4.5.7.3, and then return the PU to the SU (as per Section 4.5.7.4). In this circumstance, the EMT would maximally benefit from the expertise of the MP by delaying PU detachment as long as is practical.

4.5.7.7.2 Option Four: Sole PU is to be Transported with the Victim

[1232] If the PU is to be transported with the victim to the hospital, a replacement PU must be supplied to the arrest scene. This circumstance is referred to and discussed below in Sections 4.5.7.8.2 and 4.6.1.

4.5.7.8 Protocol Endpoints During Phase Seven

[1233] Phase seven ends when both: a) the victim is no longer attached to the PU; and b) a PU has been attached to the SU.

4.5.7.8.1 Definition of Victim Detachment from PU

[1234] The victim is no longer attached to the PU if:

[1235] a) the victim is disconnected from PU after arriving in the hospital;

[1236] b) the victim regains consciousness during the arrest, and insists on being disconnected from the PU, and leaving under his own power;

[1237] c) the EMT brings a non-PU defibrillator to the arrest, disconnects the PU from the victim, and leaves the PU at the arrest scene; or

[1238] d) the victim, after all appropriate medical and statutory consideration, is no longer considered to be a candidate for further therapeutic efforts, and is disconnected from the PU (see Sections 4.3.1.4 (h), 4.5.3.2 (b), and 4.5.5.2 (i)).

[1239] Furthermore, if, after assuming control of the PU, EMT (or physicians) wish no MP involvement, then the victim-related interaction with the system according to the invention may effectively end.

4.5.7.8.2 Circumstances in which a PU Would Not Be Promptly Replaced

4.5.7.8.2.1 PU Non-Replacement at the Arrest Site

[1240] Ordinarily, a PU is reattached to the SU. This will occur if: a) the EMT brings a new PU and the new PU is attached to the SU (option one; described in Section 4.5.7.2.1); b) the EMT brings a new PU, the new PU is attached to the victim, and the old PU is attached to the SU (option two; described in Section 4.5.7.2.2); or c) the EMT does not bring a new PU, the old PU is left at the arrest scene, and is reattached to the SU (option three; described in Section 4.5.7.7.1).

[1241] The circumstances under which reattachment of a PU to the SU would not occur are: a) although the EMT brings a new PU, no one attaches it to the SU; or b) the EMT does not bring a new PU and takes the old PU (attached to the victim) to the hospital (option four; 4.5.7.7.2). In either of these two circumstances, a person responsible for maintaining the portable units (see Section 4.6.1) will have to be dispatched to the scene, to ensure PU replacement.

4.5.7.8.2.2 Non-Replacement of the EMT PU

[1242] The PU which EMT brought to the hospital may be left there (see Section 4.1.8). If so, either EMT must later retrieve and restock it, or a person responsible for maintaining the portable units (see Section 4.6.1) will have to be dispatched to the hospital to retrieve it.

4.6 Post-Arrest Issues

[1243] Two types of PU and SU maintenance procedures assure that the equipment is ready and optimized for future use. These procedures: a) confirm that the PU is properly stocked and prepared for subsequent events; and b) confirm the proper functioning and integrity (both physical and operational) of the PU and SU; and c) replace or update PU hardware or software as needed.

4.6.1 On-Site Equipment Inspection and Assessment

[1244] The first type of maintenance procedure involves periodic on-site visits to each PU or PU/SU combination by a person whose duty it is to inspect, assess, repair, update and/or replace portable and stationary units. This person may be: a) from, or related to the same organization that includes the central station and/or the medical professional; or b) from another organization whose function is to maintain portable and stationary units.

4.6.1.1 Timing of the On-Site Visit

[1245] An on-site visit must occur:

[1246] a) if neither enabler, EMT or any other person reattached a PU to the SU, at the arrest scene, at the time of previous PU use;

[1247] b) if EMT is no longer has a PU, having previously had one (see Section 4.5.7.8.2.2, above);

[1248] c) if a PU has been damaged as a result of vandalization, or has been stolen;

[1249] d) if the amount of any disposable items in a PU (spare versions of which are kept in the PU tool-kit) has fallen below an acceptable number;

[1250] e) if any non-disposable item (e.g. wireless headset) ordinarily kept in a PU tool-kit is found to be missing;

[1251] f) if, during a remote equipment assessment and inspection (see Section 4.6.2, below), a PU and/or SU malfunction is detected which can not be remedied from a remote location; or

[1252] g) if a hardware update or replacement is required.

An on-site visit may occur:

[1253] a) after any use of a portable unit;

[1254] b) if there is a question of attempted vandalization of, or tampering with a PU, even though it functions properly during a remote inspection and assessment;

[1255] c) in order to replace or update software; or

[1256] d) on a periodic basis, even if a PU and SU show no definitive signs of needing direct attention.

4.6.1.2 Items Assessed During the On-Site Evaluation Process

[1257] The duties of this person performing this inspection and assessment include (but are not limited to):

[1258] a) performing any post-arrest housekeeping functions which were not done, were not completed, or were not done properly, at the time when enabler (or other designated person) was requested to perform them;

[1259] b) restocking any necessary disposable items (such as electrode pad(s)) which may have been used during the last event(s);

[1260] c) restocking any non-disposable items (such as scissors 170, headset 168) which may not have been properly replaced at the time of the last use;

[1261] d) replacing one or more rechargeable PU and or SU batteries (see below), if necessary;

[1262] e) inspecting and assessing areas and parts of the system which are not easily assessed by the video camera including but not limited to:

• • [1263] (i) cables 212A, 212B, 214, 216, 217, 222, 224, 226, 228 and 229 which link already hooked up electrode pads within the PU tool-kit (FIG. 7B);
  • [1264] (ii) universal connectors 218A-E and 220A-E, checking for damage or pin misalignment;
  • [1265] (iii) telephone cable 176 within the PU tool-kit (FIG. 7A);
  • [1266] (iv) oximetry sensor 174 and the cable which links it to the PU (FIG. 7A);
  • [1267] (v) blood pressure apparatus 172 and its link to the PU;
  • [1268] (vi) headset 168;
  • [1269] (vii) connectors 186, 188 on the rear surface of the PU and the front surface of the SU 190, 192;
  • [1270] (viii) PU antenna 162 and and SU antenna 164, making sure neither is bent or broken, and that the motorized deployment mechanism, if any, is sound;
  • [1271] (ix) video camera 154 (FIG. 6A) and its extensible boom 112 (FIG. 6b); and
  • [1272] (x) SU locking projection 194 (FIG. 9) and the PU-SU lock and its associated sensors;

[1273] f) inspecting and assessing the SU connection with the public telephone network;

[1274] g) inspecting and assessing the SU power connection;

[1275] h) cleaning and/or disinfecting any part of the system which may require such procedure; and

[1276] i) replacing a PU, SU, or both, if (i) it cannot be properly made ready for future use, or (ii) a newer, improved version of it has become available (see Section 4.6.3, below). The replacement may involve an entire unit or one or more parts, circuit boards or components of the unit(s).

4.6.2 Remote Equipment Inspection and Assessment

[1277] The second type of maintenance procedure involves the confirmation of proper PU and SU functioning by performing periodic remote diagnostic evaluation of both the PU and the SU. The evaluation may occur over any or all of the communications modalities which link: a) the PU/SU; and b) the CS or another diagnostic facility (see Section 4.6.2.1). The person performing the inspection and assessment may be the MP or another technically qualified person. In order to perform this process, a command is sent to the PU which causes the master control unit 130 to enter master control state 4 (see Table 1 and Section 1.3.1.2 and below). FIGS. 55A and 55B (discussed below) show the flow diagrams related to such diagnostic checking. FIG. 41 (discussed below) shows the screen menu which allows the person performing the inspection to do so.

4.6.2.1 Timing of the Remote Evaluation Process

[1278] A remote inspection and assessment:

[1279] a) occurs after the PU has been used, as soon as a replacement PU is attached to the SU (see Section 4.5.7.4.4).;

[1280] b) may be periodically initiated from the outside by (i) the central station or (ii) another diagnostic facility with equipment similar to that of the central station but not necessarily staffed by medical professionals;

[1281] c) may be periodically initiated by the PU (see below), on a routine basis; and

[1282] d) may be initiated by the PU at non-routine times, if it detects a fault (e.g. low voltage).

4.6.2.2 Items Assessed During the Remote Evaluation Process

[1283] This inspection and assessment includes but is not limited to:

[1284] a) the PU battery;

[1285] b) the SU battery;

[1286] c) the position of all PU sensor switches;

[1287] d) all connectors;

[1288] e) high voltage circuitry within the PU;

[1289] f) the electrode pads;

[1290] g) blood pressure and oxygen saturation sensors;

[1291] h) the connection with the public telephone network;

[1292] i) the PU transmitters and receivers;

[1293] j) the SU transmitters and receivers;

[1294] k) the PU external audio and video elements;

[1295] l) the wireless headset;

[1296] m) the PU global positioning system; and

[1297] n) clocks within the PU/SU.

[1298] In addition, the PU can be used to inspect itself by using the video camera 154. This can be done by (i) extending the video boom 112, and (ii) having it turn back on itself, thus causing it to become U-shaped, and thereby allow the camera to look back at the PU. This same technique can be used to determine if the PU screens 156 are performing properly. An alternative technique for visualizing the PU and its screens would involve a mirror placed on a wall opposite the PU. The video camera could be pointed at the mirror to allow PU/SU inspection and assessment.

4.6.3 PU and SU Hardware and Software Updates

[1299] From time to time, improved versions of the PU hardware or software may become available.

[1300] Hardware may be replaced at the time of an on-site visit. Hardware replacement may include: a) individual PU or SU parts, circuit boards, or components; or b) the entire PU or SU. Hardware may be replaced because of: a) a malfunctioning part, circuit board, component or unit; or b) the desire to replace a part, circuit board, component or unit with one which is newer or has improved features.

[1301] Software may be replaced or updated (i) during a PU on-site visit, or (ii) remotely, by downloading it from the central station via any of the communication modalities available between the CS and the PU/SU (see below).

[1302]

TABLE 14
Flow Diagrams of Events During a Cardiac Arrest
	Event	FIG.
	1)	Communications handshake, PU component	12
	2)	Communications handshake, CS component	13
	3)	Data/Commands handshake between	14
		portable unit and central station
	4)	Audio handshake between enabler and	15
		medical professional
	4)	Informational handshake between	16A
		enabler and medical professional
	5)	PU-SU Lock Release	16B-C
	6)	Enabler transports portable unit to victim	17
	7)	Medical professional directs enabler	18
		in portable unit setup
	8)	Medical professional assesses rhythm	19
	9)	Medical professional administers	20-23
		defibrillation and pacing, as needed
	10)	Confirmation and Error Signals	24

[1303]

TABLE 15
Central Station Screen Summary
FIG.	Screen Content
25	Communication Status and Triage
26	Voice Prompts
27	Portable Unit Deployment
28	Video Control and Instruction
29	Initial ECG
30	Electrode Matrix Pad Setup
31	Five Electrode Pad Setup
32	Multiple Single Electrode Pad Setup
33	Main Defibrillation
34	Defibrillation Energy
35	Synchronization
36	Pulse Contour
37	Antitachycardia Pacing Parameters
38	Main Pacing
39	Pacing Amplitude
40	Bradycardia Pacing Rate
41	MP-Directed Portable Unit Check and Maintenance
42	Master Triage
43	Main Screen Menu
44	Command Confirmation and Event Log

[1304]

TABLE 16
Signals During Communication (Layer #1) Handshake
Sent by Portable Unit:	Sent by Central Station:
PU-1	Button Press	CS-1	Button Press Received
PU-2	Intact Handshake	CS-2	Intact Handshake
PU-3	CS-4 Received	CS-3	PU-4 Received
PU-4	No CS Signal Received	CS-4	No PU Signal Received
PU-5A	Pseudo-Button Press:	CS-5	Pseudo Button Press
	Fault Detected During		Received
	PU-initiated Daily
	Self-Diagnostic Check
PU-5B	Pseudo-Button Press:
	PU Call to CS for
	Routine Monthly
	Self-Diagnostic Check
PU-6	Pseudo-Button Press:	CS-6	Diagnostic Check
	CS-6 Received		Initiated by CS
Note:
The format in this table applies to direct PU-CS handshakes. An analogous format may be used for a PU-SU handshake, for a SU-CS handshake, or for a handshake between any two units in which a communication handshake is attempted.

[1305]

TABLE 17
Testing During Data/Commands (Layer #2) Handshake
	COMPONENT:
	1A	1B	2	3A	3B	4	5	4B	6A	6B	7	8A	8B
Confirmation #1	X												X
Confirmation #2	X	X										X	X
Confirmation #3	X	X	X	X						X	X	X	X
Confirmation #4	X	X	X	X	X				X	X	X	X	X
Test Signal									X	X	X	X	X
MP Receiving					X				X	X	X	X	X
Voice Prompt = MP (VP)
Key
1A = CS Audio Input
1B = CS Transmitter
2 = CS to PU Routing
3A = PU Receiver
3B = PU Audio Output
4A = Enabler Hearing
4 = Enabler Cooperation
4B = Enabler Speaking
6A = PU Audio Input
6B = PU Transmitter
7 = PU to CS Routing
8A = CS Receiver
8B = CS Audio Output
X = Explicit Testing of Component

[1306]

TABLE 18
Testing During Audio (Layer #3) Handshake
	COMPONENT:
	1A	1B	2	3A	3B	4A	4	4B	6A	6B	7	8A	8B
MP Hearing EN = MP							X	X	X	X	X	X	X
(EN)
EN Hearing					X	X	i	i	i	i	i	i	I
Voice Prompt = EN (VP)
EN Hearing MP = EN	X	X	X	X	X	X	i	i	i	i	i	i	i
(MP)
Key
1A = CS Audio Input
1B = CS Transmitter
2 = CS to PU Routing
3A = PU Receiver
3B = PU Audio Output
4 = Enabler Hearing
5 = Enabler Speaking
6A = PU Audio Input
6B = PU Transmitter
7 = PU to CS Routing
8A = CS Receiver
8B = CS Audio Output
X = Explicit Testing of Component
i = Implicit Testing of Component
Note:
It is also possible to test the stationary unit transmitters and receivers during the audio handshake. Such testing is not explicitly addressed in this table.

[1307]

TABLE 19
Testing During Enabler-MP Handshake:
Which Tests are Abnormal for Each Component Failure
	TEST:
	VSE	SE	LE	VLE	MP(AB)	MP(VP)	MP(EN)	EN(VP)	EN(MP)
1A fails	−	−	−	−	+	+	+	+	−
1B fails	+	−	−	−	+	+	+	+	−
2 fails	+	+	−	−	+	+	+	+	−
3A fails	+	+	−	−	+	+	+	+	−
3B fails	+	+	+	−	+	−	+	−	−
4A fails	+	+	+	+	+	+	+/−	−	−
4 fails	+	+	+	+	+	+	+/−	−	−
4B fails	+	+	+	+	+	+	−	+	+
6A fails	+	+	+	−	−	−	−	+*	+*
6B fails	+	+	−	−	−	−	−	+*	+*
7 fails	+	+	−	−	−	−	−	+*	+*
8A fails	+	−	−	−	−	−	−	+*	+*
8B fails	−	−	−	−	−	−	−	+*	+*
Key
+ All components evaluated by this test: properly functioning.
− One or more components evaluated by this test: not properly functioning.
+/− Test result may be positive or negative.
+* Enabler hears MP or VP, but MP is not aware of this.
1A = CS Audio Input
1B = CS Transmitter
2 = CS to PU Routing
3A = PU Receiver
3B = PU Audio Output
4 = Enabler Hearing
5 = Enabler Speaking
6A = PU Audio Input
6B = PU Transmitter
7 = PU to CS Routing
8A = CS Receiver
8B = CS Audio Output
X = Explicit Testing of Component
i = Implicit Testing of Component
Note:
It is also possible to test the stationary unit transmitters and receivers during the audio handshake. Such testing is not explicitly addressed in this table.