Method and Apparatus for Providing Supplemental Temperature Controlled Bottles of Sterile Fluid

1. Technical Field

The present invention pertains to improvements in the method and apparatus for providing sterile surgical saline solution in the operating theater. In particular, the invention simultaneously provides temperature controlled basins for surgical fluid and accessible integral temperature controlled storage for supplemental containers of the required liquid and is an improvement of the methods and apparatus disclosed in U.S. Pat. No. 4,393,659 (Keyes et al), U.S. Pat. No. 4,934,152 (Templeton), U.S. Pat. No. 5,163,299 (Faries, Jr. et al), U.S. Pat. No. 5,331,820 (Faries, Jr. et al), U.S. Pat. No. 5,333,326 (Faries, Jr. et al), U.S. Pat. No. 5,400,616 (Faries, Jr. et al) and the aforesaid U.S. patent application Ser. No. 08/399,976. The entire disclosures in these patents and patent applications are expressly incorporated herein.

2. Discussion of the Prior Art

Some surgical procedures require that an accessible supply of temperature controlled surgical slush be maintained for cooling organs or body parts. In some instances warmed sterile surgical saline is mixed with the slush to produce chilled sterile fluid at selectively controlled temperatures.

A surgical slush producing system having a cabinet with a heat transfer basin at its top is disclosed in U.S. Pat. No. 4,393,659 (Keyes et al). A refrigeration mechanism in the cabinet takes the form of a closed refrigeration loop including: an evaporator in heat exchange relation to the exterior of the heat transfer basin; a compressor; a condenser; and a refrigeration expansion control, all located in the cabinet. A separate product basin is configured to be removably received in the heat transfer basin and separated from the basin by spacers.

During use, the space between the product basin and the heat transfer basin is filled with a liquid such as alcohol or glycol serving as a thermal transfer medium between the two basins. A sterile sheet of material impervious to the thermal transfer medium is disposed between the product basin exterior and the liquid thermal transfer medium to preserve the sterile nature of the product basin. Surgically sterile liquid, such as sodium chloride solution, is placed in the product basin and congeals on the basin side when the refrigeration unit is activated. A scraping tool is used to remove the congealed sterile material to form slush of desired consistency in the basin.

Subsequently, U.S. Pat. No. 4,934,152 (Templeton) disclosed an improved apparatus wherein the product basin function is replaced in favor of a sterilized drape impervious to the sterile surgical liquid, the drape being made to conform to the basin and directly receive the sterile liquid. Congealed liquid is scraped from the conformed drape side to form the desired slush. The Templeton patent also discloses a system having two operating modes. In one mode the basin is cooled to a temperature below the freezing point of the sterile liquid. In the other mode the contents of the basin are heated to a temperature slightly elevated with respect to normal body temperature, typically on the order of 105.degree. F.

In a more recent improvement disclosed in U.S. Pat. No. 5,429,801 (Faries et al), a surgical slush machine is provided with two operating modes, a first mode operating in the range of -10.degree. F. to -70.degree. F. (nominally about -40.degree. F.) for rapidly bringing sterile liquid temperature down to its freezing temperature, and a second mode operating in the range of 20.degree. F. to 40.degree. F. for maintaining the basin near the freezing temperature of the medium.

Placing selectively and individually temperature controlled basins for providing surgical slush and warmed sterile liquid in close adjacency is disclosed in U.S. Pat. No. 5,333,326 (Faries et al). This arrangement allows the surgical staff to adjust the consistency of the sterile slush by the selective addition of warmed sterile solution, and further supports the availability of more than a single sterile compound as is occasionally required in some surgical procedures. What has not heretofore been readily and conveniently available has been an auxiliary supply of bottled sterile compound maintained at appropriate chilled and warmed temperatures for timely replenishment of the contents of the basins. Specifically, it is desirable to pre-chill or pre-warm the stored sterile liquid in order to reduce the time required to achieve desired temperature after the liquid is poured into the drape container. Storing additional bottles in separate warming and cooling units outside the surgical theater necessitates inefficient and time-consuming passage into and out of the operating room by otherwise better occupied medical personnel during the procedure.

It is an object of the present invention to provide a method and apparatus for simultaneously providing basins for maintaining surgical sterile fluid at preselected temperatures and integral temperature controlled storage for bottles of supplemental sterile liquid.

It is another object of the present invention to provide and maintain supplemental supplies of warmed bottled sterile solution for use during surgical procedures.

It is a further object of the present invention to provide and maintain supplemental supplies of chilled bottled sterile solution for use during surgical procedures.

It is an additional object of the present invention to allow replenishment of surgical solution in temperature controlled basins from bottles of solution maintained at similar temperatures in storage cabinets collocated with the basins.

It is yet another object of the present invention to minimize the time and effort required to replace or replenish surgical solution in basins in surgical theaters to improve operating efficiency.

The aforesaid objects can be achieved individually and in combination and it is not intended that the invention be construed as requiring that two or more of said objects be combined.

In accordance with the present invention insulated temperature controlled storage is provided in the basin support cabinet, depending either on independent heating and cooling units or drawing directly from the heating and cooling units provided for basin temperature control. Warmed bottles of sterile surgical solution may be stored in a first storage section and chilled bottles of solution stored in a second storage section, each accessed by optionally transparent doors providing visual indication to operating personnel of supplies on hand.

The above and still further objects, features and advantages of the present invention will become apparent from consideration of the following detailed description of specific embodiments thereof, particularly when taken in conjunction with the accompanying drawings wherein like components are designated by like reference numerals.

FIG. 1 is a perspective view of a combined surgical slush and warmed sterile liquid cabinet having integral temperature-controlled storage space according to the present invention.

FIG. 2 is an electrical schematic diagram of the cooling system employed by the present invention.

FIG. 3 is an electrical schematic diagram of the heating system employed by the present invention.

A mobile surgical fluid support cabinet 10 according to the present invention is shown in FIG. 1. A first basin 12 formed in the top surface 14 of cabinet 10 maintains sterile surgical fluid in a chilled slush-like state and a second basin 16 also formed in cabinet top surface 14 maintains a second supply of the same or a different surgical fluid in a warmed state. Disposed on the top surface 14 of cabinet 10 are a cooling unit power switch 18, a cooling unit temperature controller/indicator 20, a heater power switch 22 and a heater unit temperature controller/indicator 24. A sterile drape (not shown), made of a material impervious to the sterile fluids, preferably transparent to allow observation and manipulation of temperature controls therethrough and flexible enough to conform to the concave surface of basins 12 and 16, may be extended over the cabinet top to provide sterile and disposable fluid receptacles within the two basins.

Within cabinet 10, separate temperature-controlled insulated compartments 28 and 30 maintain supplemental sealed bottles 32 of the required fluids in the desired chilled and warmed conditions, respectively, relative to ambient temperature (which in a surgical theater is normally 72.degree. F.). Access to the supplemental bottles 32, or other materials useful in surgical procedures, is through cabinet doors 34, preferably at least partially transparent to allow easy visual monitoring of supplies on hand by operating room personnel. As the supply of surgical fluid in basins 12 and 16 becomes depleted or requires temperature modulation, closed bottles 32 of the appropriate fluid are removed from the cabinet and the contents transferred to the corresponding basin.

Refrigeration components are illustrated schematically in FIG. 2 including a compressor 36 selectively actuable by means of an electrical power source 38 and an on-off power switch 18. The compressor 36 causes a suitable refrigerant fluid to flow through a series circuit including a condenser 42, one or more evaporator sections 44a and 44b, and a suitable thermal expansion valve 45. A first evaporator portion 44a is disposed about the sides of cooling basin 12 to permit cooling of the basin to a desired temperature, and a second evaporator portion 44b is disposed around chilled or refrigerated compartment 28. A temperature sensor 46 is disposed along the outside surface of the bottom of basin 12 to monitor the temperature of slush formed therein. Sensor 46 is connected in series with a voltage source 48, preferably derived from power source 38, and indicator 50. Indicator 50 measures the current passing through sensor 46 which, in turn, is proportional to the temperature in basin 12. The sensed temperature can then be compared to a predetermined desired temperature and the results of the comparison used to control flow of refrigerant through the evaporators and thus control the basin and storage compartment temperatures, using any number of conventional circuit alternatives. The desired temperature is established by the setting of the controller/indicator 20 on cabinet top 14.

Heating components, illustrated schematically in FIG. 3, include a power source 52 connected in series with a temperature control unit 54, a first heater element 56a disposed along the bottom surface of heating basin 16, power control switch 22, and a second heater element 56b disposed in parallel with first heater element 56a and located along the bottom surface of warmed compartment 30. Temperature control unit 54 includes a device for adjusting the current passing through the heating elements 56a and 56b to permit selective adjustment of the heat applied to the liquid in basin 16 and in bottles 32 stored in space 30. The power switch 22 permits selective application and removal of current flow with respect to heaters 56a and 56b.

A temperature sensor 66 is disposed adjacent basin 16 to sense the temperature of the liquid therein. Sensor 66 is connected in series with a voltage source 68 and an indicator 70. Voltage source 68 and power source 52 may be the same source, or the voltage for one may be derived from the other. Indicator 70 measures the current through temperature sensor 66, that current being proportional to the sensed temperature. Indicator 70 and temperature controller 64 may correspond, for example, to the temperature controller/indicator described above.

The temperature maintained in chilled compartment 28 may be controlled and monitored independently with respect to the basin temperature by additional sensors and controllers or, alternatively, independent and separate refrigeration circuits can be provided for the cooling basin 12 and the chilled compartment 28. Similarly independent sensors and controllers can be provided for the warmed compartment of the heating circuit of FIG. 3 or separate independent heating circuits can be supplied for the basin 16 and the warmed storage compartment 30. Moreover, a single heat exchange system similar to, for instance, a heat pump, with thermostatically controlled ductways, can provide appropriate temperature control for both warmed and chilled basins and associated storage compartments. Chilled and warmed compartments 28 and 30, respectively, are maintained at appropriate long-term storage temperatures while basins 12 and 16 are actuated only during periods of surgical activity requiring readily accessible sterile fluids.

Storage access doors 34 shown in FIG. 1 are attached by hinges 80 to the cabinet and formed of insulating yet transparent material, such as glass or lucite, to allow operating room personnel to determine with a glance the inventory of chilled and warmed sterile fluid bottles available to supplement the basins. Storage of warmed bottles is illustrated above the storage of chilled fluid for thermal efficiency but side by side storage or other configurations are contemplated as feasible depending on the available space and the preferences of the operating room personnel. Obviously, the concept of collocated supplemental sterile solution storage of the present invention is equally applicable to single basin cabinets and to cabinets supporting three or more separate fluids and corresponding temperature requirements as it is to the illustrated two-basin example and as well to cabinets designed to accommodate separate product basins rather than a sterile drape arrangement disposed to conform to cabinet top cooling and warming basins.

In use, bottles of the sterile solutions required by a particular surgical procedure are prepared and stored in the appropriate temperature controlled compartments 28 and 30, respectively, prior to commencement of the procedure. The power control switches 18 and 22 are actuated and temperature controller/indicators 20 and 24 are adjusted to achieve and maintain desired chilling and warming temperatures, respectively, in the basins and compartments. The temperature in chilled compartment 28 is maintained between ambient temperature and the freezing temperature of the sterile medium in bottles 32, preferably very close to that freezing temperature, in order to reduce the time required to achieve the desired chilled temperature of the basin when the medium is used. Likewise, the temperature in warmed compartment 30 is maintained between ambient and the regulated heater basin temperature, preferably very close to that basin temperature. Measured amounts of pre-cooled or warmed solution are added to the two basins for ready access by the surgical personnel. As additional solution is required to resupply depleted basins, to quickly adjust solution temperature or to replace contaminated volumes, bottles of solution, observable through the transparent doors 34, are retrieved from the appropriate storage compartment and added to the top surface basin or basins.

Alternatively, the cabinet is kept in a power-on condition with appropriate storage temperatures maintained in chilled and warmed compartments 28 and 30, respectively. Prior to a surgical procedure requiring the sterile solutions, bottles of appropriate fluid are transferred from storage and poured into the basins and the basin heating and cooling systems are actuated to proper temperature.

From the foregoing description, it will be appreciated that the current invention makes available a novel surgical solution system and method for maintaining readily observed and accessed supplemental supplies of prepared fluid at required warmed and chilled temperatures to minimize the time, effort and disruption of operating room procedure.

Having described preferred embodiments of a new and improved method and apparatus for providing supplemental supplies of temperature-conditioned sterile solution, it is believed that other modifications, variations and changes will be suggested to those skilled in the art in view of the teachings set forth herein, it is therefore to be understood that all such variations, modifications and changes are believed to fall within the scope of the present invention as defined by the appended claims.