Procedure alarm silence feature for medical telemetry system

[0002] A variety of medical telemetry systems exist which allow the ECG waveforms of hospital patients to be monitored in real time. The ECG signals of the patient are sensed by a telemeter unit and a set of ECG leads, and are transmitted by the telemeter unit to a monitoring station (typically located in a central location). In ambulatory systems, the telemeter units are battery-powered wireless units that are worn by the patients. The telemeter units may also be designed to sense and transmit other types of physiologic data such as pulse oximetry, non-invasive and invasive blood pressure, end tidal carbon dioxide, respiration, and temperature.

[0003] The monitoring station, which typically includes a PC or other computer system coupled to a receiver, displays the ECG waveforms of multiple patients for viewing by a human operator. The monitoring station also applies software-implemented analysis algorithms to check for abnormalities, such as arrhythmia conditions, high and low alarm limits, and lost signals caused by loose leads. When such an abnormality is detected, an alarm indicator is displayed on the screen, and/or an audible alarm is sounded.

[0004] One problem with existing medical telemetry systems is that false alarms frequently occur as the result of short-term procedures performed on the patients by nurses and other clinicians. For example, a false alarm may occur when a clinician replaces or repositions the ECG leads for patient. As a result, clinicians are unnecessarily dispatched to patients' rooms or otherwise distracted.

[0005] The present invention overcomes this problem by providing a “procedure alarm silence” feature through which a clinician can remotely disable the alarm from the bedside or other patient location for a predetermined time. The feature is preferably invoked by the clinician through a predefined sequence of key depressions or other actions on the telemeter unit. Once invoked, the monitoring station temporarily inhibits some or all types of alarms. In a preferred embodiment, for example, the monitoring station disables the audible alarm for a two minute interval for all monitored abnormalities except class 1 arrhythmia conditions. A corresponding visual alarm is preferably kept active. The predefined key sequence is preferably selected such that patients and clinicians are unlikely to invoke the feature (disable audible alarms) by accident.

[0006] FIG. 1 illustrates the operation of an example telemeter unit and monitoring station according to the present invention.

[0007] An example implementation of the invention will now be described with reference to FIG. 1, which is intended to illustrate but not limit the invention. The scope of the invention is defined by the appended claims.

[0008] As depicted in FIG. 1, the ambulatory telemeter units 30 (one shown) of the system include four types of buttons or keys: a Remote Record key 34, a Nurse Call key 36, a Procedure Alarm Silence (PAS) key 38, and a pair of Attendant Present/Procedure Alarm Silence Unlock keys 40 (preferably positioned on opposite sides of the telemeter unit). The functions performed by these keys are summarized in Table 1. The telemeter unit 30 also includes a “PAS Unlocked” LED 42 which flashes indicating that the PAS key is unlocked and can be actuated by pressing the PAS key. The keys illustrated in FIG. 1 are for illustrative purposes only, and are not intended to imply actual key sizes or locations.

[0009] The default state of the PAS key 38 is “locked” (non-functional). To unlock the PAS key, the clinician holds down both Attendant Present/Procedure Alarm Silence Unlock keys 40 until the “PAS unlocked” LED 42 begins flashing. As depicted by the telemeter flow diagram in FIG. 1, if the PAS key is not thereafter pressed within a preprogrammed “unlocked” period, the LED stops flashing and the PAS key is returned to the locked state. If, on the other hand, the PAS key is pressed while unlocked, a PAS message is sent to the central station 32 (monitoring system), causing the central station to enter into the PAS mode (audible alarms disabled, etc.) for the particular telemeter unit 30 and patient. The central station remains in the PAS mode with respect to that patient until expiration of a preprogrammed PAS interval, such as two minutes, or until the PAS key is re-pressed, whichever occurs first.

[0010] As illustrated by the central station flow diagram, upon receiving the PAS message and entering into the PAS mode, the central station 32 disables the audible alarm for all but class 1 arrhythmia alarm conditions. The visual alarms preferably remain active. While in the PAS mode, a message such as “Temporary Procedure Alarm Silence Activated,” and a visual indication of the amount of time remaining in the PAS interval, are displayed on a central station display screen 32A in association with the particular patient's data. Once either a “PAS Reset” message is received from the telemeter unit 30 (indicating a “PAS re-press” event) or the PAS interval expires, the PAS message and “time remaining” indicator are cleared from the display and the audible alarms are re-enabled.

[0011] As will be apparent from the foregoing, any of a variety of alternative key types and key depression sequences could be used to remotely disable the alarms. In addition, other types of clinician actions could be used to initiate the PAS mode, such as applying a magnetic or electronic key to the telemeter unit. Further, although the feature is illustrated in connection with a wireless, ambulatory telemeter unit, the feature may be incorporated into hardwired and other non-ambulatory telemeter units.