Abstract:
Apparatus for altering the body temperature of a patient comprises an inflatable mattress defining an interior space for receiving at least a portion of a patient&#39;s body therein. The inflatable mattress is constructed to conduct a heat transfer liquid into direct contact with the portion of the patient&#39;s body. The inflatable mattress includes a first zone inflatable to a first pressure and a second zone inflatable to a second pressure greater than the first air pressure. The inflatable mattress in an inflated condition defines a well for receiving the portion of the patient therein. A head positioner positions the patient&#39;s head so that the patient&#39;s breathing passageway remains out of contact with the heat transfer fluid. A method of adjusting the body temperature of a patient comprises filling the first and second zones, positioning the portion of the patient&#39;s body on the mattress, and directing the heat transfer liquid to contact the patient&#39;s body.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a continuation-in-part of co-pending U.S. application Ser. No. 10/948,918 filed Sep. 24, 2004, which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention generally relates to medical apparatus for altering the body temperature of a patient and more particularly to apparatus that enables efficient, quick adjustment of the body temperature of a patient, especially to induce hypothermia.  
         [0003]     Sudden cardiac arrest remains a serious public health issue. Approximately 350,000 individuals are stricken in the United States annually, with overall survival rates of roughly 5 percent. Even with the immediate availability of the most advanced care currently available, including cardiopulmonary resuscitation (CPR), drugs, ventilation equipment, and automatic external defibrillators, a survival rate of 25 percent may be the probable best case scenario. Improved therapies to deal with this condition are clearly needed.  
         [0004]     Numerous incidences of recovery following accidental hypothermia and cardiac arrest have been reported. This observation has led researchers to consider therapeutic hypothermia as a possible treatment for reducing the adverse consequences of circulatory arrest. Various studies have shown that mild systemic hypothermia (approximately 3-5° C. (5.4-9.0° F.)) can reduce damage to vital organs, including the brain. Hypothermia induced both during and following cardiac arrest has demonstrated this benefit. The use of cardiopulmonary bypass has also been effective in rapidly achieving this goal. Direct flushing of cooled fluids into the arterial system has also been employed with success. Both invasive measures, however, require large bore intravascular catheters and rapid introduction of sterile solutions into the patient. Such invasive approaches have obvious disadvantages in dealing with out-of-hospital emergencies.  
         [0005]     Noninvasive cooling, if sufficiently effective and portable, would be a preferable approach. Direct cooling of the head alone has produced variable results. However, post-resuscitative cooling of the entire body to approximately 33° C. (91.4° F.) by noninvasive treatment has been demonstrated to be surprisingly effective in recent clinical studies. The use of cold gel and ice packs produced cooling of approximately 0.9° C. (1.6° F.) per hour, and resulted in a nearly 100 percent improvement in neurologically intact survival (Bernard S. A. et al.,  Treatment of Comatose Survivors of Out - of - Hospital Cardiac Arrest with Induced Hypothermia,  346 New Eng. J. Med. 557-563 (2002)). In another study, cold air was found to be capable of cooling patients at a rate of about 0.25° C. (0.45° F.) per hour, which caused a 40 percent improvement in the same endpoint (Sterz F. et al.,  Mild Therapeutic Hypothermia to Improve the Neurologic Outcome after Cardiac Arrest,  346 New Eng. J. Med. 549-556 (2002)). In yet another study, a combination of water-filled cooling blankets and ice packs applied to the skin resulted in a cooling rate of 0.8° C. (1.4° F.) per hour (Felberg et al.,  Hypothermia After Cardiac Arrest—Feasibility and Safety of an External Cooling Protocol,  104 Circulation 1799-1804 (2001)). It is believed that increasing the rate of cooling from what is shown in these studies may produce a higher rate of patient salvage.  
       SUMMARY OF THE INVENTION  
       [0006]     In one aspect of the present invention, apparatus for altering the body temperature of a patient generally comprises an inflatable mattress defining an interior space for receiving at least a portion of a patient&#39;s body therein. The inflatable mattress is constructed to conduct a heat transfer liquid into direct contact with the portion of the patient&#39;s body received in the interior space to promote heat transfer between the patient&#39;s body and the heat transfer liquid. The inflatable mattress includes a first zone inflatable to a first pressure and a second zone inflatable to a second pressure greater than the first air pressure. The inflatable mattress in an inflated condition defines a well for receiving the portion of the patient therein.  
         [0007]     In another aspect of the present invention, a method for adjusting the body temperature of a patient generally comprises filling a first zone of a compliant support with a fluid to a first pressure, and filling a second zone of the compliant support with a fluid to a second pressure greater than the first pressure. The filled compliant support is adapted to support and substantially underlie a portion of the patient&#39;s body. At least a portion of a patient&#39;s body is positioned on the compliant support. A heat transfer liquid is directed to flow over the patient&#39;s body in direct liquid contact therewith to promote heat transfer between the patient&#39;s body and the heat transfer liquid.  
         [0008]     In still another aspect of the present invention, apparatus for adjusting the body temperature of a patient generally comprises an enclosure defining an interior space for receiving at least a portion of a patient&#39;s body therein. The enclosure is adapted to contain a heat transfer fluid for direct contact with the portion of the patient&#39;s body received in the enclosure to promote heat transfer between the patient&#39;s body and the heat transfer fluid. A head positioner is for positioning the patient&#39;s head so that the patient&#39;s breathing passageway remains out of contact with the heat transfer fluid. The positioner is adapted to flank the sides of patient&#39;s head thereby prevent the head of the patient from rotating from side to side.  
         [0009]     Other objects and features will be in part apparent and in part pointed out hereinafter. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective of an apparatus of the present invention in use for altering the body temperature of a patient lying in the apparatus on a gurney;  
         [0011]      FIG. 2  is a top plan of the apparatus of  FIG. 1 ;  
         [0012]      FIG. 3  is a side view of the apparatus with portions of an enclosure thereof broken away;  
         [0013]      FIG. 4  is a top plan of a cover of the enclosure;  
         [0014]      FIG. 5  is an exploded perspective of the cover;  
         [0015]      FIG. 6  is an enlarged fragmentary section on line  6 - 6  of  FIG. 4 ;  
         [0016]      FIG. 7  is an enlargement of a fragment of the cover as indicated in  FIG. 5 ;  
         [0017]      FIG. 8  is a top plan of a compliant support of the enclosure with parts broken away to show internal construction;  
         [0018]      FIG. 9  is an exploded perspective of the compliant support;  
         [0019]      FIG. 10  is a section on line  10 - 10  of  FIG. 8 ;  
         [0020]      FIG. 11  is an enlarged fragment of the compliant support shown in  FIG. 10 ;  
         [0021]      FIG. 12  is a perspective of a drain tube for the compliant support;  
         [0022]      FIG. 13  is a perspective of a housing for a weir;  
         [0023]      FIG. 14  is an exploded perspective of the housing;  
         [0024]      FIG. 15  is a section on line  15 - 15  of  FIG. 13  showing the weir in a flow restricting position;  
         [0025]      FIG. 16  is the section of  FIG. 15  but showing the weir in a non-restricting position;  
         [0026]      FIG. 17  is a perspective of a mobile cart housing a control system with portions of the cart broken away to show an air pump and a controller of the control system;  
         [0027]      FIG. 18  is a perspective of the mobile cart showing a hinged lid of the cart opened;  
         [0028]      FIG. 19  is the perspective of  FIG. 18  but showing a pump housing and a reservoir partially removed from the cart;  
         [0029]      FIG. 20  is a perspective showing the pump housing and reservoir removed from the cart;  
         [0030]      FIG. 21  is an enlarged, fragmentary section on line  21 - 21  of  FIG. 20 ;  
         [0031]      FIG. 22  is a perspective of an umbilicus for fluidly connecting the mobile cart to the cover and compliant support;  
         [0032]      FIG. 23  is an exploded perspective of the umbilicus;  
         [0033]      FIG. 24  is a plan view of a monitor of the mobile cart displaying a user interface for the control system; and  
         [0034]      FIG. 25  is a schematic of the control system.  
         [0035]     Corresponding reference characters indicate corresponding parts throughout the drawings.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]     Referring now to the drawings and particularly to  FIGS. 1-3 , reference number  10  generally indicates an apparatus for adjusting the body temperature of a patient P. The apparatus  10  generally comprises an enclosure, indicated at  14 , defining an interior space  16  for receiving a patient&#39;s body. The enclosure  14  is adapted to allow heat transfer liquid  18  ( FIG. 17 ), such as water, saline, or other suitable liquids, to flow into the interior space  16  for direct contact with the patient&#39;s body to promote heat transfer between the patient P and the heat transfer liquid. In the illustrated embodiment, the interior space  16  of the enclosure  14  is configured to receive the entire body of the patient P, including the torso, arms, and legs ( FIGS. 1-3 ). As a result, the amount of surface area of the patient P available for contact by the heat transfer liquid  18  is maximized. It is to be understood that the enclosure  14  can be configured to receive less than the patient&#39;s entire body. That is, the enclosure  14  can be configured to receive only a portion of the patient&#39;s body.  
         [0037]     The enclosure  14  is adapted to generally conform to the shape of the body of the patient P received therein to accommodate patients of various shapes and sizes. For example, in the illustrated configuration, the enclosure  14  is suitable for patients having a size between about the 5th percentile and about the 95th percentile adult male. Other enclosures adapted to receive smaller patients (e.g., babies, children, small adults) or larger patients are also contemplated. Although the patient P is most commonly a human, the apparatus  10  could be configured for and used for altering the body temperature of other animals. More detail regarding the conforming shape of the enclosure  14  is provided below.  
         [0038]     As illustrated in  FIGS. 1-3 , the enclosure  14  comprises a cover, indicated at  22 , for overlying the patient P from the neck downward, and a compliant support, indicated at  24 , for underlying the patient&#39;s entire body. As shown in  FIGS. 2 and 3 , the cover  22  is limp so that it generally conforms, under its own weight, to the contours of the upward facing surface of the patient&#39;s body it is covering. To this end, the cover  22  includes two foot gussets  26  located in a portion of the cover adapted to receive the feet of the patient P. The foot gussets  26  allow the cover  22  to more readily conform to the contours of the patient P near the feet of the patient. Each of the foot gussets  26  comprise a pocket for receiving a respective foot of the patient P thereby preventing the feet of the patient from creating a tent affect in the cover  22  ( FIG. 3 ). In other words, each of the foot gussets  26  are sized and shaped for receiving and conforming to one of the feet of the patient P. It is to be understood that the foot gusset can be formed as a single pocket adapted to receive both of the patient&#39;s feet therein.  
         [0039]     With reference to  FIGS. 4-7 , the cover  22  comprises a generally limp sheet-like body-facing component  28  and a generally limp sheet-like outer component  30  that are in face-to-face engagement with one another. In the illustrated configuration, the outer component  30  is significantly smaller than the body-facing component  28  to conserve material. It will be understood that the outer component  30  and body-facing component  28  can have the same size, or the outer component can have a size greater than the body-facing component.  
         [0040]     The body-facing and outer components  28 ,  30  are liquid impermeable and joined to one another along their facing sides to form a plurality of passages  32  therebetween for allowing the heat transfer liquid  18  to flow through the cover  22 . Heat sealing is used to seal the components  28 ,  30  together along seams  34  to form the passages  32  because it provides adequate strength without requiring additional raw materials (e.g., adhesive). Other methods of forming the passages  32  or sealing the components  28 ,  30  to one another, such as adhesives, are also contemplated as being within the scope of the present invention.  
         [0041]     The passages  32  in the cover  22  are configured to distribute heat transfer liquid  18  over a large portion of the surface area of the patient&#39;s body. Specifically, the illustrated cover  22  is configured to distribute heat transfer liquid  18  over the patient P from the neck downward (see,  FIGS. 1 and 2 ). As illustrated in  FIG. 4 , each of the passages  32  extend generally longitudinally of the enclosure  14  and have a width of approximately 25 mm and a height of approximately 3 mm. It is to be understood that the dimensions provided for the passages  32  are exemplary only and that the passages can be formed to have various dimensions. It is also understood that the passages  32  can extend in directions relative to the enclosure  14  other than longitudinal (e.g., lateral, oblique) and need not be parallel to one another.  
         [0042]     Before the passages  32  are filled with heat transfer liquid  18 , the sheet-like body-facing component  28  and sheet-like outer component  30  of the passage generally lie flat against one another. Once heat transfer liquid  18  flows inside the passage  32 , however, the cross-sectional area of the passage increases to allow heat transfer liquid to flow between the components  28 ,  30  ( FIG. 6 ). The weight of the heat transfer liquid  18  in the passages  32  causes the cover  22  to further conform to the contours of the patient&#39;s body. Since the passages  32  extend throughout much of the cover  22 , the majority of the cover is weighted against the body of the patient P by the heat transfer liquid. It is to be understood that the passages  32  formed in the cover  22  can have hold-opens (not shown) for maintaining the increased cross-sectional area of the passages even when heat transfer liquid is not flowing through the passages. Hold-opens are described in further detail below.  
         [0043]     The body-facing component  28  of the cover  22  includes a plurality of openings  36  (i.e., inlets) therein corresponding to the passages  32  for allowing the heat transfer liquid  18  to pass from the passages to the portion of the patient&#39;s body received in the enclosure  14  ( FIGS. 5 and 7 ). Each opening  36  is generally circular and preferably has a diameter of about 1 millimeter (0.04 inches). The openings  36  are shown enlarged in the accompanying Figures so that they can be seen. The small diameter openings  36  restrict the flow of heat transfer liquid  18  from the passages  32  into the enclosure  14  thereby causing the entire length of the passages to fill with heat transfer liquid. As a result, the heat transfer liquid  18  is evenly distributed via the passages  32  to each of the openings  36 . A doghouse connector  38  is affixed to the outer component  30  of the cover  22  for fluidly connecting the passages  32  in the cover to a liquid delivery system. The liquid delivery system is described in detail below.  
         [0044]     The number of openings  36  positioned in various portions of the cover  22  may be varied to regulate the distribution of heat transfer liquid  18  throughout the enclosure  14 . As illustrated in  FIG. 5 , the openings  36  in the cover  22  are positioned for generally evenly distributing the heat transfer liquid  18  over the top of the patient&#39;s body. Heat transfer liquid  18  is directed through the doghouse connector  38  and into the passages  32  such that the heat transfer liquid flows from a bottom section B (i.e., the lower one-third) of the cover  22 , through a middle section M (i.e., the middle one-third) of the cover to a top section T (i.e., the top one-third) of the cover ( FIG. 4 ). To even the flow distribution, the number of openings  36  increases along the length of the passages  32  in a direction away from the bottom section B of the cover  22  ( FIG. 5 ). Thus, the middle section M of the cover  22  has a greater number of openings  36  than the bottom section B, and the top section T has a greater number of openings than the middle section.  
         [0045]     In another configuration (not shown), the diameters of the openings  36  are varied along the length of the passages  32  in a direction away from the bottom section B of the cover  22 . Using this approach, openings  36  having smaller diameters are positioned near the bottom sections B of the cover  22  while openings with progressively larger diameters are positioned in the middle and top sections M, T of the cover.  
         [0046]     It is to be understood that numerous configurations for the openings  36  are possible to adequately distribute heat transfer liquid  18  to the body of the patient P by varying the size, shape, and distribution of the openings. It is also understood that the openings  36  in the cover  22  may be positioned to distribute heat transfer liquid  18  unevenly throughout the interior space  16  of the enclosure  14 . By having an uneven flow distribution, a greater volume of heat transfer liquid  18  can be directed to selected portions of the patient&#39;s body, such as those more amenable to heat transfer (e.g., the head, neck, torso), than other non-selected portions of the patient&#39;s body, which are also received in the enclosure  14 .  
         [0047]     The configuration of the passages  32  and openings  36  illustrated in  FIGS. 4 and 5  is particularly useful where CPR is to be administered to the patient P while the patient is in a supine position in the interior space  16  of the enclosure  14 . During CPR, the chest of the patient P is compressed through the limp cover  22  generally along the medial line of the patient. As a result, any passages  32  in the cover  22  corresponding approximately with the medial line of the patient P could be repeatedly blocked as the patient&#39;s chest is compressed thereby reducing the flow of heat transfer liquid  18  to the interior space  16  of the enclosure  14 . Since a number of the passages  32  and openings  36  are offset from the medial line of the patient P, the chest compressions performed during CPR are less disruptive of fluid flow through the enclosure  14 . In other words, chest compressions can be performed on the patient P while the patient is received in the interior space  16  of the enclosure  14  (i.e., directly through the cover  22 ) with minimal disruption of flow of heat transfer liquid  18  to the patient.  
         [0048]     In the illustrated embodiment, the cover  22  is made of a transparent material, such as polyvinyl chloride (PVC), polyethylene, or polyurethane, so that the body of the patient P received within the interior space  16  of the enclosure  14  can be viewed through the cover. It is to be understood, however, that the cover  22  can be made of a non-transparent material or have a portion that is transparent and a portion that is non-transparent.  
         [0049]     With reference now to  FIGS. 8-12 , the compliant support  24  is a pneumatic support, which (like the cover  22 ) generally conforms to the shape of the patient&#39;s body when the body rests on the support. Moreover, the compliant support  24  minimizes pressure concentrations beneath the patient P which facilitates the flow of heat transfer liquid  18  beneath the patient and minimizes the possibility of pressure sores developing in the skin of the patient. Generally, the compliant support  24  comprises an inflatable base  42  (broadly, a “first zone”), which is the portion of the compliant support upon which the patient P rests, and two generally oblong, inflatable tubes  44 A,  44 B (broadly, a “second zone”) forming a periphery around the base. In the illustrated embodiment, one of the inflatable tubes  44 A is arranged on top of the other tube  44 B. It is to be understood, however, that more or fewer (i.e., one) inflatable tubes  44 A,  44 B can be used to form the periphery of the base  42 . It is also to be understood that the inflatable tubes could be disposed side-by-side instead of one on top of the other.  
         [0050]     The stacked inflatable tubes  44 A,  44 B and base  42  cooperatively form a watertight well, generally indicated at  46 , for receiving the entire body of the patient P therein. The well  46  is configured to generally conform to the body of the patient P thereby minimizing the volume of the interior space  16  of the enclosure  16  and the amount of heat transfer liquid  18  necessary to effectively alter the body temperature of the patient P. More specifically, the patient P is positioned in a supine position on the base  42  with the base and the tubes  44 A,  44 B in a deflated state. The base  42  and inflatable tubes  44 A,  44 B are then inflated to enclose the patient&#39;s body within the well  46  and generally conform the well to the profile of the patient&#39;s body. As the inflatable tubes  44 A,  44 B are filled with air (or other suitable gas), the tubes generally conform to the sides of the patient P. The base  42  is typically inflated to a pressure that is less than the inflated pressure of the inflatable tubes  44 A,  44 B. As a result, the base  42  easily conforms to the contours of the patient P because of the patient&#39;s weight. More specifically, the weight of the patient P causes the base  42  to assume a bowl-shape that is tailored to the patient&#39;s body ( FIG. 3 ). The base  42  and inflatable tubes  44 A,  44 B can be inflated manually or with an air pump. It is to be understood that the compliant support  24  may have different shapes and sizes or be conformable with the patient&#39;s body in a way different from that described herein.  
         [0051]     With reference to  FIG. 8 , the well  46  comprises a pocket  48  sized and shaped for receiving the head and neck of the patient P, a broader region  50  for receiving the torso of the patient, and a tapered pocket  52  for receiving the legs and feet of the patient. The pocket  48 , which is adapted for receiving the head and neck of the patient P, is configured to support the head in an upward-facing direction thereby maintaining the patient&#39;s breathing passageways (i.e., nose and mouth) out of contact with the heat transfer liquid  18 . The pocket  48  prevents the head of the patient P from moving to a side-facing direction and holds the head of the patient at a relatively higher position than the torso of the patient. It is to be understood that a head rest (not shown) can be used to support the patient&#39;s head. The head rest can be formed as one-piece with the compliant support  24  or provided separately.  
         [0052]     The broader region  50  of the well  46  further includes a pair of shoulder gussets  54  for receiving the shoulders of the patient P. The shoulder gussets  54  allow the base  42  to expand in the shoulder region of the patient P, which is often the broadest region of the patient, to accommodate patients with varying shoulder widths.  
         [0053]     As illustrated in  FIG. 3 , the well  46  is deeper in the broader region  50  receiving the torso of the patient P than in the pocket  48  receiving the head or the tapered pocket  52  receiving the legs and feet since a large portion of the patient&#39;s weight is contained in the torso. More specifically, the well  46  has a depth D in the broader region  50  adapted to receive the torso between about 2.5 centimeters (1 inch) and about 20 centimeters (8 inches), and preferably between about 10.2 centimeters (4 inches) and about 15 centimeters (6 inches), which correspond generally to about one-half of the chest heights of adult males between the 5th percentile and 95th percentile.  
         [0054]     The variation in depths in the well  46  allows more heat transfer liquid  18  to accumulate around the torso of the patient P, a region of the body amenable to heat transfer, than around the head, legs, and feet of the patient P. The reasons for managing the depth of the heat transfer liquid  18  in the pocket  48  adapted to receive the head of the patient P are apparent and explained previously herein. It is to be understood that the well  46  can have a generally uniform depth D or have depths different from those indicated without departing from the scope of this invention. For example, an enclosure designed for use with smaller adults, children, or babies, would have depths less than those disclosed herein.  
         [0055]     With reference to  FIGS. 9 and 10 , the illustrated compliant support  24  is formed using four flexible sheet-like components. As illustrated, a first component  56 A and a second component  56 B are paired together, and a third component  56 C and a fourth component  56 D are paired together. The paired components  56 A,  56 B and  56 C,  56 D are placed in face-to-face engagement with one another and joined at first seals  58 A,  58 B that extend around the peripheries thereof and at second seals  58 C,  58 D that are spaced inward from the peripheries. The portions of the components  56 A-D located between the first seals  58 A,  58 B and the second seal  58 C,  58 D cooperatively define the inflatable tubes  44 A,  44 B. Particularly, the paired first and second components  56 A,  56 B form the lower tube  44 B, and the paired third and fourth components  56 C,  56 D form the upper tube  44 A. Referring again to  FIG. 9 , a respective doghouse connector  60  extends into each of the portions of the components  56 A-D located between the first seals  58 A,  58 B and the second seals  58 C,  58 D for allowing the inflatable tubes  44 A,  44 B to be inflated using an exterior air source (i.e., manually or an air pump).  
         [0056]     The paired first and second components  56 A,  56 B forming the lower tube  44 B are overlaid by the paired third and fourth components  56 C,  56 D forming the upper tube  44 A and sealed together. More specifically and with reference to  FIG. 10 , the third component  56 C is sealed to the second component  56 B along a continuous seal  57  to define a sealed chamber  62  that is formed between the joined first and second components  56 A,  56 B and the joined third and fourth components  56 C,  56 D. The sealed chamber  62  is inflatable and, when inflated, underlies and provides support for the patient P received in the well  46 . A doghouse connector  64  extends into the sealed chamber  62  for allowing air to be introduced into the sealed chamber  62  to thereby inflate the base  42  using a suitable exterior air source.  
         [0057]     A porous layer  66  is used to cover the well  46  so that the porous layer is disposed between the body of the patient P and the fourth component  56 D ( FIGS. 3 and 10 ). The porous layer  66 , such as rich loft polyester batting or open-cell polyurethane foam, allows heat transfer liquid  18  to flow between the body of the patient P and the well  46  and thereby across the skin of the patient. The porous layer  66  prevents areas of the well  46  from being sealed off from the body of the patient P contacting the fourth component  56 D, which would inhibit flow of heat transfer liquid  18  beneath the body of the patient.  
         [0058]     With reference to  FIGS. 8, 10 , and  11 , the third and forth components  56 C,  56 D also cooperatively define a plurality of supply passages  68  for allowing heat transfer liquid  18  to be supplied beneath the body of the patient P, and two return passages  70  for allowing heat transfer liquid to be drained from the well  46 . The illustrated supply and return passages  68 ,  70  are formed using heat sealing but it is to be understood that other methods of forming the passages  68 ,  70  or sealing the components  56 C,  56 D to one another, such as adhesives, can be used. The passages  68 ,  70  have a length approximately equal to the about half the length of the compliant support  24  and are generally located in the broader region  50  of the well  46 .  
         [0059]     Since the return passages  70  rely on gravity for fluid flow, the return passages are substantially larger in cross-section than the supply passages  68  ( FIG. 11 ). The supply passages  68  can be sized smaller since a pump is used to drive heat transfer liquid  18  into the passages. A reinforcing layer  72  is attached to the third component  56 C beneath the passages  68 ,  70  to provide additional structural integrity to the passages. It is to be understood that the number, location, and dimensions provided herein for the passages  68 ,  70  are exemplary only and that more or fewer passages can be formed and that the passages can be formed to have various dimensions, various location on the compliant support.  
         [0060]     Referring now to  FIGS. 10 and 11 , each of the passages  68 ,  70  formed in the compliant support  24  are supported by a hold-open  74 , which holds the passages open and permits flow of the heat transfer liquid  18  through the passage past the hold-open. The hold-opens  74  provide the rigidity necessary to maintain the passages  68 ,  70  open even when subjected to a load, such as the weight of the body of the patient P which bears on the passages formed in the well  46 . The hold-open  74  may be a porous material, such as open-celled foams, particulate matter (e.g., polystyrene beads), batting, non-woven materials, or mechanical devices, such as coil springs. One suitable open-celled foam is a reticulated polyurethane foam having approximately 25 pores per inch manufactured by Foamex of Eddystown, Pa., USA, and sold under the trade name SIF®.  
         [0061]     With reference again to  FIGS. 8 and 9 , the fourth component  56 D of the compliant support  24  has a plurality of openings  76  (i.e., inlets) therein corresponding to the supply passages  68  for allowing the heat transfer liquid  18  to pass from the passage into direct fluid contact with the underside of the patient&#39;s body received in the well  46 . Each of the illustrated openings  76  is generally circular and has a diameter of about 1 millimeter (0.04 inches). The openings  76  are enlarged in the accompanying figures so that they can be seen. The small diameter openings  76  restrict the flow of heat transfer liquid  18  from the passage  68  into the enclosure  14  thereby causing the entire lengths of the passages to fill with heat transfer liquid and evenly distributing the heat transfer liquid along the lengths of the passages.  
         [0062]     The forth component  56 D also has a plurality of larger sized apertures  78  (i.e., outlets) therein corresponding to the return passages  70  for allowing heat transfer liquid  18  to exit the well  46 . The return passages  70  and the well  46  of the compliant support  24  are fluidly connected to at least one large diameter (e.g., 2.5 centimeters (1 inch)) outlet  80  extending through all four of the sheet-like components  56 A-D for draining heat transfer liquid  18  from the well. It is contemplated that the large diameter outlet  80  may be larger or smaller than 2.5 centimeters. The illustrated outlet  80  is preferably sufficiently sized to allow heat transfer liquid  18  to be drained from the well  46  by gravity at a rate equal to or greater than the rate at which the heat transfer liquid is being delivered to the interior space  16  of the enclosure  14  to prevent the enclosure from overflowing. Moreover, the illustrated large diameter outlet  80  is located in the broader region  50  of the well  46 , which is adapted to receive the torso of the patient P. As indicated above, the broader region  50  is typically the deepest portion of the well  46  or, in other words, the lowest portion of the well. As a result, large diameter outlet  80  is located in what is typically the lowest portion of the well  46 . The well  46  may have more than one outlet  80 , the outlet may be positioned at other sections of the enclosure, and the outlet may have other sizes and shapes.  
         [0063]     Referring to  FIGS. 9 and 12 , a drain tube  82  is fluidly connected to the large diameter outlet  80  for transferring heat transfer liquid  18  away from the interior space  16  of the enclosure  14 . At least a portion of the drain tube  82  is located underneath the compliant support  24 . As a result, the drain tube  82  is provided with at least one hold-open  84  to keep the drain open during use of the apparatus  10 . In the illustrated configuration, the hold-open  84  for the drain tube  82  are two, elongate inflatable tubes that flank the sides of the drain. One of the elongate inflatable tubes is located adjacent one side of the drain tube  82  and the other inflatable tube is located adjacent the opposite side of the drain tube. It is to be understood that other types of hold-opens  84 , including those described above, could be used or that the drain tube  82  could be formed from material with sufficient rigidity as to not warrant the use of the hold-open.  
         [0064]     With reference now to  FIGS. 1 and 13 - 16 , a weir  86  (broadly, “a flow restrictor”) is in fluid communication with the drain tube  82  and the large diameter outlet  80  for maintaining the depth D of the heat transfer liquid  18  within the well  46  at a predetermined level thereby allowing the heat transfer liquid to accumulate in the well adjacent and beneath the patient P. Specifically, a drain tube outlet  83  is attached to a weir inlet  85  so that heat transfer liquid flowing from the interior space  16  of the enclosure  14  flows through the drain tube  82  and into the weir  86 . It is to be understood that the flow restrictor may be a device besides the weir  86 , such as an inverted U-shaped tube or an adjustable valve, without departing from the scope of this invention.  
         [0065]     The weir  86  includes a dam  87  of a predetermined height which the heat transfer liquid  18  must flow over before it is drained from the enclosure  14  ( FIG. 13 ). For instance, if the heat transfer liquid  18  is maintained at a depth of between about 7 centimeters (2.8 inches) and about 15 centimeters (6 inches) in the well  46 , the weir  86  needs to have a height H sufficient to prevent heat transfer liquid below the selected height from flowing out of the well. Since the weir  86  maintains heat transfer liquid  18  at a given depth D in the well  46 , the weir creates a positive gage pressure as measured at the large diameter outlet  80 , which would between about 0.69 kilopascals (0.1 pounds per square inch) and about 1.47 kilopascals (0.2 pounds per square inch) for the well  46  with a depth of heat transfer liquid between 7 centimeters (2.8 inches) and about 15 centimeters (6 inches).  
         [0066]     The weir dam  87  is located in a weir housing  88  and cooperates with the housing  88  to selectively retard the flow of heat transfer liquid  18 . As illustrated in  FIG. 14 , the weir dam  87  comprises a generally rectangular web affixed to shaft  89 . A cap  91  of the weir housing  88  is also affixed to the shaft  89  but is spaced from the weir dam  87 . The cap  91  is rotatably secured to the weir housing using a clamp  93 . The cap  91  includes a handle  90  for rotating the cap  91  and thus, the shaft  89  and weir dam  87  with respect to the housing  88 .  
         [0067]     The handle  90  can be used to selectively move the weir  86  between a flow restricting position ( FIG. 15 ) wherein the weir dam  87  creates a spillway which the heat transfer liquid  18  must flow over before it is exhausted from the well  46 , and a non-restricting position ( FIG. 16 ) wherein the weir dam is rotated and substantially allows the heat transfer liquid to flow unimpeded from the well. The non-restricting position of the weir  86  is used to rapidly purge the interior space  16  of the enclosure  14  of heat transfer liquid  18 . A weir outlet  95  allows heat transfer liquid  18  that has passed over the weir dam  87  to exit the weir housing  88 . It is to be understood that the flow restrictor could be automatically moved between the restricting position and non-restricting position using a controller, which is described below.  
         [0068]     As illustrated in  FIG. 1 , the weir housing  88  is secured by an upper support  92 A and a lower support  92 B integrally formed with the compliant support  24 . The upper and lower supports  92 A,  92 B are adapted to hold the weir housing  88  and thereby the weir  86  in proper alignment with respect the compliant support  24 .  
         [0069]     As shown in  FIGS. 1 and 2 , the cover  22  and the compliant support  24  are adapted for engagement with each other. The cover  22  includes a first sealing portion  94  ( FIG. 4 ) and the support  24  includes a second sealing portion  96  ( FIG. 8 ) for engaging with the first sealing portion  94 . The sealing portions  94 ,  96  allow the cover  22  to be completely or partially removed from compliant support  24 . In the illustrated embodiment, the sealing portions  94 ,  96  comprise a hook and loop fastening system. For example, a strip of hook material is shown adhered to the compliant support  24 , and a strip of loop material is shown adhered to the cover  22  for engaging the hook material located on the compliant support. It is to be understood that the loop material can be placed on the compliant support  24  and the hook material on the cover  22 . It is also understood that other types of fastening systems (e.g., adhesives, slide fasteners, snaps) can be used. It is further understood that a portion of the cover  22  can be bonded to the compliant support  24  to thereby hingedly attach the cover to the compliant support.  
         [0070]     The cover  22  is slightly smaller than the support  24  which allows the sealing portions  94 ,  96  of both the cover and the compliant support to lie above and laterally inward from the sides of the support. As a result, the sealing portions  94 ,  96  are positioned away from the medial line of the patient P received in the interior space  16  of the enclosure  14  thereby allowing CPR to be administered to the patient without interference from the sealing portions.  
         [0071]     Furthermore, the sealing portions  94 ,  96  are positioned on a portion of the enclosure  14  that is maintained generally horizontal. As a result, the potential for the sealing portions  94 ,  96  to be bent or otherwise deformed is minimized. Bending and deformation of the sealing portions  94 ,  96  may diminish the ability to seal or to be opened or closed. Moreover, the sealing portions  94 ,  96  are positioned at a location above the depth D at which heat transfer liquid  18  accumulated in the well  46  of the compliant support  24 , which reduces the demand on the sealing portions (i.e., the sealing portions do not have to form water tight seals). Lastly, the sealing portions  94 ,  96  are conveniently located for a user thereby providing the user with easy access to the patient P.  
         [0072]     Referring now to FIGS.  1 ,  17 - 19 , and  25 , the apparatus  10  further comprises a control system, generally indicated at  100 , for controlling operation of the apparatus  10 . The control system  100 , which is mounted on a mobile cart  98 , includes a controller  102 , a monitor  104  (broadly, a “user interface”), a delivery system, and a temperature sensor  108  for measuring the temperature of the patient P. The monitor  104  includes a LCD touch screen display for visually indicating particular parameters of the control system  100  and for allowing the user of the system to selectively control particular system functions ( FIG. 24 ). The monitor  104 , for example, could display a target temperature along with the actual body temperature of the patient P, and the temperature of the heat transfer liquid  18 , among other things. With respect to user control of the system  100 , the user can start, pause, and stop the delivery system using the touch screen display of the monitor  104 . It is also understood that other system  100  functions could be controlled by the user using the touch screen display of the monitor  104 .  
         [0073]     The delivery system of the control system  100  comprises the liquid delivery system and a gas delivery system. The liquid delivery system is a generally closed, continuous flow system in which heat transfer liquid  18  is cycled through the interior space  16  of the enclosure  14 . The liquid delivery system comprises a fluid reservoir  112 , two liquid inlet pumps, generally indicated at  114 , with disposable gear pumpheads contained within a housing  140  driven by motorized drive gears  115 , and an umbilicus  120 . The umbilicus  120  fluidly connects the reservoir  112  and two liquid pumps  114  to the interior space  16  of the enclosure  14 . It is to be understood that the delivery system can have fewer or more components without departing from the scope of this invention.  
         [0074]     The reservoir  112  holds heat transfer liquid  18  before the pumps  114  pump the heat transfer liquid into the interior space  16  of the enclosure  14 . The reservoir  112  may have insulation (not shown) to help maintain the temperature of the heat transfer liquid  18  before it is pumped into the enclosure  14 . Although various sized reservoirs may be used, the reservoir  112  in the illustrated embodiment has a capacity sufficient to hold about 30 liters (about 8 gallons) of heat transfer liquid  18 . It is to be understood that reservoirs having different capacities may be used. For example, a reservoir for holding heat transfer liquid for the child or baby sized enclosure may have a smaller capacity where as a reservoir for holding heat transfer liquid for a larger enclosure may have a larger capacity.  
         [0075]     A phase change material  122  (e.g., ice) is also placed into the reservoir  112  to alter and/or maintain the temperature of the heat transfer liquid  18  to an inlet temperature, measured before the liquid enters the enclosure  14  ( FIG. 17 ). In the illustrated embodiment, approximately 10 liters (2.6 gallons) of ice  122  are placed into the reservoir  112  but other quantities of ice could be used. Moreover, additional ice  122  can be added to the reservoir  112 , if necessary, during the operation of the apparatus  10  to maintain the heat transfer liquid  18  at the desired inlet temperature. Besides phase change materials  122 , various other types of heat exchangers (e.g., Peltier device) are contemplated as being within the scope of the present invention.  
         [0076]     The illustrated reservoir  112  comprises a plastic bag removable supported in the mobile cart by a frame  124  with handles ( FIG. 19 ). Moreover, the mobile cart includes a reservoir viewing window  126  for allowing the user to visually observe the ice  122  and heat transfer liquid  18  contained in the reservoir  112 . The window  126  has a heat transfer fill line  128  to indicate the level to which heat transfer should be placed into the reservoir, and an ice and heat transfer fill line  130  to indicate the level to which ice  122  should be added to the heat transfer liquid in the reservoir. Ice  122  and heat transfer liquid  18  can be added to the reservoir  112 , as necessary, during operation of the apparatus  10 . It is contemplated that the ice  122  could be added to the reservoir  112  before heat transfer liquid  18 . It is also contemplated the ice  122  and heat transfer liquid  18  could be pre-measured before placing them into the reservoir  112 .  
         [0077]     As illustrated in  FIGS. 18-21 , the reservoir  112  has two integrated passages  132  formed by heat sealing a separate sheet of material  134  to the bag. The passages  132  are used as intake passages for the pumps  114  ( FIG. 19 ) for allowing the pumps to draw heat transfer liquid  18  from the reservoir  112  through the passages. The passages  132  include hold-opens  136  (as described above) to prevent the pumps  114  from drawing closed the passages during use ( FIG. 21 ). The passages  132  have openings  138  adjacent the bottom of the reservoir  112 , which prevents the buoyant ice  122  from being drawn into the pumps  114  while allowing the heat transfer liquid  18  to be drawn into the pumps ( FIG. 20 ). It is to be understood that passages  132  can be formed separately from the reservoir  112  and could be formed from conventional polymeric tubing.  
         [0078]     The two inlet pumps  114  are in fluid communication with the passages  132  formed in the reservoir  112 , the umbilicus  120 , and the passages  32 ,  68  in the enclosure  14  so that the pumps can pump heat transfer liquid  18  from the reservoir into the enclosure. More specifically, one of the pumps  114  directs heat transfer liquid  18  to the passages  32  in the cover  22  for directing heat transfer liquid  18  over the top of the body of the patient P, and the other inlet pump directs heat transfer liquid to the passages  68  in the compliant support  24  thereby directing heat transfer liquid underneath the patient&#39;s body.  
         [0079]     Each of the pumps  114  can be operated independently of the other. Accordingly, heat transfer liquid  18  can be selectively directed for flow over the top of the body of the patient P, underneath the patient&#39;s body, or both (i.e., simultaneously over the top of the patient&#39;s body and underneath the patient&#39;s body). In the illustrated embodiment, one of the pumps  114  is capable of transferring liquid to the passages  32  in the cover  22  at a flow rate of about 8 liters per minute (2.1 gallons per minute). The other pump  114  is capable of directing heat transfer liquid  18  to the passages  68  in the compliant support  24  at a flow rate of about 6 liters per minute (1.6 gallons per minute). Thus, the two pumps  114  are capable of pumping heat transfer liquid  18  into the interior space  16  of the enclosure  14  at a flow rate of about 14 liters per minute (3.7 gallons per minute). It is to be understood that the pumps can have capacities other than those described herein and that a single pump or more pumps can be used to pump heat transfer liquid  18  into the interior space  14  of the enclosure  16 .  
         [0080]     The pumps  114  described above were specifically designed gear pumps for use in this apparatus  10  ( FIG. 9 ). However, the pumps  114  can be conventional gear pumps, such as the UGP-2000 series manufactured by B&amp;D Pumps, Inc. of Huntley, Ill., USA, or a roller-type pumphead with a motor drive, such as the 500 series process pump manufactured by Watson-Marlow OEM of Paramus, N.J., USA. Should higher flow rates or other parameters be required, alternative pumps, such as higher capacity gear or centrifugal pumps, may be used without departing from the scope of the present invention.  
         [0081]     Both of the pumps  114  incorporate detachable pumpheads (not shown) that are contained in the housing  140  ( FIGS. 18-20 ). The housing  140  and thus, the pumpheads are disposable to minimize the likelihood of cross-contamination to subsequent patients. The pumpheads are the only part of the pumps  114  that contact the heat transfer liquid  18 . In the illustrated embodiment, the pumphead housing  140  is held in place using a rotatable hold-down  142 . As illustrated in  FIG. 18 , the hold-down  142  can be rotated to a position above the pumphead housing  140  thereby supporting the pumphead housing in position. As shown in  FIG. 19 , the hold-down  142  can be rotated so that the hold-down is clear of the pumphead housing  140  thereby allowing the pumphead housing and thereby the pumpheads to be removed from the pumps  114  and the mobile cart  98 . Accordingly, after use, the pumpheads can be removed from the pumps  114 , discarded properly, and a new pumpheads (i.e., a new pumphead housing  140 ) installed on the pump for use with the next patient.  
         [0082]     The control system  100  further includes the gas delivery system for delivering pressurized air to inflate the various inflatable components of the compliant support  24 . The gas delivery system comprises an air pump  116  and a plurality of pressure sensors  144  ( FIG. 17 ). As shown, the air pump  116  and sensors  144  are located in a housing  146  of the mobile cart  98 , and a portion of the housing  146  is shown broken away to expose the air pump and sensors. The air pump  116 , such as a conventional reciprocating or scroll-type compressor, is in fluid communication with the compliant support  24  for inflating the inflatable tubes  44 A,  44 B, the sealed chamber  62 , and the drain hold-opens  84 . For example, the pump  116  may have the capacity to fill the inflatable tubes  44 A,  44 B of the compliant support  24  with air at a rate of about 500 liters per minute to a positive gauge pressure of about 3.4 kilopascals (0.5 pounds per square inch), the sealed chamber  62  to a positive gauge pressure of about 0.76 kilopascals (0.11 pounds per square inch), and the drain hold-opens  84  to a positive gauge pressure of about 3.4 kilopascals (0.5 pounds per square inch). It is to be understood that other types of air pumps can be used and that the air pumps can have different flow rates then those indicated.  
         [0083]     The pressure sensors  144 , which are shown in  FIG. 17 , are adapted to measure the air pressure within at least the inflatable tubes  44 A,  44 B and the sealed chamber  62  of the compliant support  24 . In the illustrated configuration, one pressure sensor  144  is positioned within a first air line  143  that communicates with the inflatable tubes  44 A,  44 B and a second pressure sensor is positioned within a second air line  145  that communicates with the sealed chamber  62 . But the gas delivery system could have more or fewer pressure sensors  144  without departing from the scope of this invention.  
         [0084]     The pressure sensors  144  are connected to the controller  102  so that their air pressure measurements are conveyed to the controller so that the controller can compare the detected pressure measurements to predetermined pressures. The controller  102  is further connected to the air pump  116  so that if the detected measurements differ from the predetermined pressures, the controller can activate the pump to bring the air pressures within the inflatable tubes  44 A,  44 B and the sealed chamber  62  to about the predetermined pressures. Accordingly, should air leaks occur during operation of the apparatus  10 , the air pump  116  will be activated, as necessary, to maintain the proper air pressures within the complaint support  24 .  
         [0085]     Referring to  FIGS. 22 and 23 , the umbilicus  120  is used to simply and easily connect the heat transfer liquid pumps  114  and the air pump  116  to the enclosure  16 . The umbilicus  120  includes two flexible air supply conduits  148  for supplying air from the air pump  116  to the inflatable tubes  44 A,  44 B, the sealed chamber  62 , and the drain tube hold-opens  84 . Specifically, one of the air supply conduits  148  feeds the inflatable tubes  44 A,  44 B and the drain tube hold-opens  84  and the other air supply conduit feeds the sealed chamber  62 . The umbilicus also includes two flexible liquid supply conduits  150  fluidly connect the heat transfer liquid pumps  114  to the enclosure  16 . One of the liquid supply conduits  150  is used to feed liquid to the cover  22  and the other is used to feed liquid to the compliant support  24 . The umbilicus  120  further includes a flexible liquid return conduit  152  that fluidly connects the drain tube  82  (via the weir housing  88 ) to the reservoir  112 . The two air supply conduits  148 , two liquid supply conduits  150 , and liquid return conduit  152  are secured together using spaced apart retainers  154 .  
         [0086]     Each end of the umbilicus  120  comprises a quick-connect coupling  160  to attach the ends of the umbilicus and thereby the conduits  148 ,  150 ,  152  to the control system  100  and the enclosure  16  to establish a fluid connect therebetween ( FIG. 2 ). More specifically, one end of the umbilicus  120  attaches to the weir housing  88  and the opposite end of the umbilicus attaches to the pumphead housing  140 . Each of the illustrated quick-connect couplings  160  comprises a first coupling member  160 A ( FIGS. 13 and 18 ) and a second coupling member  160 B ( FIG. 22 ) selectively attachable to the first coupling member by rotating the second coupling member with respect to the first coupling member less than about 180° and more preferably less than 90°.  
         [0087]     In the illustrated configuration, the second coupling members  160 B are affixed to the ends of the umbilicus  120  ( FIG. 21 ) and the first coupling members  160 A are affixed to the weir housing  88  ( FIG. 13 ) and the pumphead housing  140  ( FIG. 18 ). Each of the first and second coupling members  160 A,  160 B comprises a manifold  156  having a connector  158  for corresponding to each of the five conduits  148 ,  150 ,  152 . As a result, all five of the conduits  148 ,  150 ,  152  are connected or disconnected simultaneously by simply connecting or disconnecting the first coupling members  160 A to the second coupling members  160 B. It is to be understood, however, that other types of couplings including couplings besides quick-connect couplings and other types of quick-connect couplings can be used. It will also be understood that each of the conduits  148 ,  150 ,  152  can be individually connected to the control system  100  and the enclosure  14 .  
         [0088]     The apparatus  10  shown in the attached drawings is intended to be used a medical treatment facility (e.g., a hospital). The enclosure  14 , for example, is sized and shaped for placement on a stretcher, such as an ambulance or emergency gurney G, to facilitate the transportation of the patient P in a conventional manner while placed in the enclosure ( FIGS. 1-3 ). Accordingly, the enclosure  14  may have a width between about 66 centimeters (26 inches) and about 76 centimeters (30 inches) and a length between about 203 centimeters (80 inches) and about 210 centimeters (83 inches), the approximate range of dimensions for a standard ambulance or emergency gurney G. It is contemplated that the enclosure  14  may have other configurations without departing from the scope of this invention. For example, the enclosure  14  can be configured for a conventional hospital bed (not shown). It is also contemplated since many victims of cardiac arrest are initially treated by first responders (i.e., police officers, firefighters, emergency medical technicians), that the apparatus  10  can be made portable for use remote from a medical facility.  
         [0089]     As mentioned above, the enclosure  14  is adapted to allow heat transfer liquid  18  to flow into the interior space  16  for direct contact with the patient&#39;s body to promote heat transfer between the patient P and the heat transfer liquid. To raise the temperature of a patient P, the heat transfer liquid  18  is directed into the interior space  16  of the enclosure  14  at a temperature greater than the temperature of the portion of the patient&#39;s body. For example, the heat transfer liquid  18  may have a temperature in a range of about 43° C. (109° F.) to about 47° C. (117° F.), such as about 45° C. (113° F.). One application of such a warming enclosure would be to warm a patient P suffering from unintended hypothermia.  
         [0090]     To lower the temperature of a patient P, the heat transfer liquid  18  is directed into the interior space  16  of the enclosure  14  at a temperature lower than the temperature of the body portion of the patient received in the interior space  16  of the enclosure so that the fluid cools the body portion of the patient. For example, the heat transfer liquid  18  may have a temperature in a range of about 0° C. (32° F.) to about 5° C. (41° F.). Heat transfer liquid  18  introduced into the enclosure  14  at such a temperature has been found to cool the body at a sufficient rate to induce hypothermia while minimizing any adverse effects to the skin of the patient P. It is to be understood that temperatures other than those listed above can be used to adjust the temperature of a patient P received in the interior space  16  of the enclosure  14 .  
         [0091]     The volume of heat transfer liquid  18  necessary to effectively alter the temperature of the patient P is dependent on the size and shape of the patient. For example, a larger patient P will require more heat transfer liquid than will a smaller patient to achieve a similar rate of heat transfer. The heat transfer liquid  18  within the interior space  16  of the enclosure  14  is maintained in a relatively thin layer and near or in contact with the patient&#39;s body positioned the well  46 . As a result, the amount of heat transfer liquid  18  necessary to effectively alter the temperature of the patient P can be minimized. This becomes increasingly important in remote areas where volumes of heat transfer liquid  18 , which can become heavy, need to be carried by hand.  
         [0092]     The amount of time necessary to induce hypothermia in a patient P is dependent on numerous factors including how much of the patient&#39;s body is positioned in the interior space  16  of the enclosure  14 , the temperature of the heat transfer liquid  18 , and the amount of time the heat transfer liquid is in contact with the patient&#39;s body. As a result, the enclosure  14  is adapted to enclose substantially the entire body of the patient&#39;s thereby providing a large portion of the patient&#39;s total surface area for heat transfer with the heat transfer liquid  18 . In the illustrated configuration, the face of the patient is not enclosed.  
         [0093]     One application of cooling would be to cool a patient P suffering from cardiac arrest. It is well recognized that organ damage can, and typically does, occur shortly after the victim has suffered cardiac arrest. As a result, it is often in the victim&#39;s best interest to quickly and effectively induce hypothermia to minimize or prevent organ damage. It is also contemplated that the apparatus  10  may be used to treat other medical conditions than those listed or have application in other medical procedures (e.g., hyperthermia, trauma, stroke, enhancements of anti-cancer therapies, surgical support, and general thermal management).  
         [0094]     In operation, the enclosure  14  is placed in an uninflated state on a generally flat surface, such the ambulance gurney G. The compliant support  24  is fully extended to a position such that the underside of the compliant support is resting on the gurney G. If not already done, the cover  22  is removed from the compliant support  24  by disengaging the sealing portions  94 ,  96  to expose the center of the compliant support  24 . The patient P is carefully placed on the base  42  of the compliant support  24 . Using the touch screen display on the monitor  104 , the user activates the controller  102 . For example, as illustrated in  FIG. 24 , the user could press an inflate icon button  164  or a start button  166 . In response, the controller  102  activates the air pump  116  to inflate the tubes  44 A,  44 B, the hold-open  84  for the drain tube  82 , and the sealed chamber  62  to the desired pressure. As explained above, inflating the tubes  44 A,  44 B and the sealed chamber  62  conforms the well  46  of the complaint support  24  to the portion of the patient&#39;s body received therein.  
         [0095]     The air pump  116  can be activated anytime during use of the apparatus  10  by pressing the inflate icon button  164  to maintain the tubes  44 A,  44 B, the hold-open  84  for the drain tube  82 , and/or the sealed chamber  62  at the desired pressure. In one embodiment, the air pressure in the inflatable tubes  44 A,  44 B and the air pressure in the seal chamber  62  is monitored using pressure sensors  144  and compared to desired pressures or a range of desired pressures by the controller  102 . If the pressure in the inflatable tubes  44 A,  44 B or sealed chamber  62  falls below a threshold pressure, the air pump  116  is automatically activated by the controller  102  to re-inflate the respective component to the desired pressure.  
         [0096]     The cover  22  is placed on the patient P to cover the patient&#39;s body from the neck downward. The sealing portion  94  of the cover  22  and the sealing portion  96  of the compliant support  24  are engaged thereby enclosing the patient P in the interior space  16  of the enclosure  14 . The temperature sensor  108  (i.e., thermometer) is connected to the patient P for measuring the core body temperature of the patient. The temperature sensor  108  is also connected to the controller  102  so that the measured body temperature of the patient P can be conveyed to the controller. As shown in  FIG. 24 , the patient temperature can be displayed on the monitor.  
         [0097]     The reservoir  112  is filled with the appropriate amount of ice  122  and heat transfer liquid  18 . That is, a sufficient amount of heat transfer liquid  18  is added to the reservoir  112  to reach the heat transfer fill line  128  located on the mobile cart window  126 , and sufficient amount of ice  122  is added to reach the ice and heat transfer fill line  130  (see.  FIG. 1 ). As shown in  FIG. 24 , the reservoir temperature can also be monitored and displayed on the monitor  104 .  
         [0098]     Using the touch screen display on the monitor  104 , the delivery system  92  can be activated by pressing a run icon button  168  on the monitor. Once activated, the pumps  114  deliver heat transfer liquid  18  to the patient&#39;s body to adjust the temperature of the patient P to a selected temperature. For example, it may be desirable to quickly lower the body temperature of a patient P suffering from cardiac arrest from about 37° C. (98.6° F.) to about 33° C. (91.4° F.). As illustrated in  FIG. 24 , the target temperature of the patient P can be displayed on the monitor  104 . Moreover, the target temperature can be adjusted upward or downward by the user using an up arrow key  172  and a down arrow key  174 , respectively.  
         [0099]     In this example, approximately 30 liters (8 gallons) of the heat transfer liquid  18  (e.g., water) and approximately 4.5 kilograms (10 pounds) of phase change material (e.g., ice) would have been added to the reservoir  112 . In some instances, it may be desirable to use pre-cooled heat transfer liquid  18 . The heat transfer liquid  18 , which is lowered to a temperature between about 0° C. (32° F.) and about 5° C. (41° F.), is drawn from the reservoir  112  by the pumps  114  and pumped through umbilicus  120  and into the passages  32 ,  68  in the cover  22  and the compliant support  24  and thereby into the top and bottom of the interior space  16  of the enclosure  14 .  
         [0100]     With both pumps  114  operating, the heat transfer liquid  18  directly contacts the body of the patient P at a flow rate of about 14 liters per minute (3.7 gallons per minute). In addition to being able to pump heat transfer liquid  18  into both the top and bottom of the enclosure  14  simultaneously, the pumps  114  can be selectively operated to pump heat transfer liquid  18  only into the top of the enclosure or only into the bottom of the enclosure. In one configuration, one of the pumps  114 , such as the pump supplying heat transfer liquid  18  to the passages  32  in the cover  22 , can be deactivated by the user pressing a pause button  170  on the touch screen display of the monitor  104 . Both pumps  114  can be deactivated by the user pushing the pause button  170  a second time. Both pumps  114  can be reactivated by the user pushing the start button  166  and/or the run icon button  168 .  
         [0101]     During operation of the pumps  114 , heat transfer liquid  18  accumulates in the well  46  in the compliant support  24  such that a greater volume of heat transfer liquid accumulates in the broader region  50  of the compliant support that receives the torso than the other regions  52 ,  54  of the compliant support that receive the head, legs, and feet. The heat transfer liquid  18  accumulates in the interior space  16  of the enclosure  14  until it reaches a depth greater than height of the dam  87  of the weir  86 , which is in fluid communication with the large diameter outlet  80 . The dam  87  maintains the heat transfer liquid  18  at the target depth D of about 11 centimeters (4.5 inches), which creates a positive gauge pressure as measured at the outlet  80  of the enclosure  14  of about 1.1 kilopascals (0.16 psi). Any heat transfer liquid  18  achieving a height greater than the spillway created by the dam  87  is drained from the interior space  16  of the enclosure  14  at a flow rate equal to or greater than flow rates at which the heat transfer liquid is being driven into the interior space  16  of the enclosure  14  by the pumps  114 .  
         [0102]     The heat transfer liquid  18  is directed back into the reservoir  112  through the liquid return conduit  152  of the umbilicus  120  where it is re-cooled by the phase change material  122  before being recirculated back into the interior space  16  of the enclosure  14 . Heat transfer liquid  18  is continuously recirculated through the enclosure  14  until the patient&#39;s temperature reaches or approaches the selected temperature. The patient&#39;s temperature may drop slightly after the heat transfer liquid  18  has been stopped and, as a result, it may be desirable to stop the flow of heat transfer liquid before the patient&#39;s temperature drops to the selected temperature to prevent overshoot (i.e., lowering the patient&#39;s body temperature below the selected temperature). For example, the controller  102  can be programmed to shut off the liquid delivery system when the core body temperature of the patient is within 1° C. or 2° C. of the target temperature to prevent the patient&#39;s core body temperature from falling below the target temperature. In addition, the controller  102  can be programmed to send a warning (i.e., an audio or visual alarm) to a user if the core body temperature falls below the target temperature.  
         [0103]     Once the temperature of the patient P has reached the predetermined temperature (e.g., 1° C. or 2° C. above of the target temperature), the pumps  114  are automatically shut off by the controller  102  and the heat transfer liquid  18  is purged from the enclosure  14 . The interior space  16  of the enclosure  14  can also be purged by the user pressing a purge icon button  176 . In yet another way, the interior space  16  of the enclosure  14  can be purged by deactivating the pumps  114  by pressing the pause button  170  twice and rotating the handle  90  on the weir  86  to move the weir from the flow restricting position ( FIG. 15 ) to the non-restricting position ( FIG. 16 ).  
         [0104]     In one configuration, the interior space  16  of the enclosure  14  can be purged by allowing any heat transfer liquid  18  present in the interior space to flow via gravity through the large diameter outlet  80 , through the drain tube  82  and return conduit  152 , and into the reservoir  112 . This is done by moving the weir dam  87  from the flow restricting position to the non-restricting position. In another configuration, the interior space  16  of the enclosure  14  can be purged by reversing the pumps  114 . As a result, heat transfer liquid  18  is drawn using one of the two pumps  114  through the openings  76  in the passages  68  in the compliant support  24  and pumped back into the reservoir  112 . The other pump  114  is used to draw any heat transfer liquid  18  remaining in the passages in the cover  22  back into the reservoir  112 . In this configuration, the weir dam  87  can also be moved from the flow restricting position to the non-restricting position thereby allowing heat transfer liquid  18  to exit the interior space  16  of the enclosure  14  via gravity as well as via the pumps  114 .  
         [0105]     The inflatable tubes  44 A,  44 B, the sealed chamber  62 , and the drain hold-opens  84  of the compliant support  24  can be deflated by activating the air release valves  178  ( FIGS. 1 and 9 ). In the illustrated configuration, the air release valves  178  comprise capped plugs that can be activated by manually removing the cap from the plug housing. It is to be understood that the other types of air release valves including automated valves can be used.  
         [0106]     If necessary, CPR can be performed on a patient P received in the interior space  16  of the enclosure  14  directly through the cover  22  while heat transfer liquid  18  is being supplied to the patient. Thus, with the cover  22  covering the patient P, oxygen can by supplied to the lungs of the patient and the chest of the patient can be compressed.  
         [0107]     It is to be understood that during operation of the apparatus  10 , the user is able to maintain visual observation of the body of the patient P through the transparent cover  22 . If additional medical care is needed, the cover  22  can be partially or completely removed to expose the patient&#39;s body while the liquid delivery system remains operating. To prevent the loss of heat transfer liquid  18 , the pump  114  directing heat transfer liquid to the passages  32  in the cover  22  can be shut off before the cover is pulled back. Moreover, all of the apparatus&#39; operations can occur in the ambulance on route to the medical facility thereby not delaying any subsequent medical care.  
         [0108]     It is to be understood that the controller  102  can be programmed so that when the user presses the start button  166  on the touch screen display of the monitor  104 , the apparatus  10  automatically proceeds sequentially through the inflate, run, and purge stages of operation without further input from the user. The user, however, can interrupt operation of the apparatus  10  during any stage by pressing the pause button  170 , or can completely stop the operation of the apparatus by pressing a stop button  180 . The apparatus  10  can be reactivated from the paused or stopped position by the user pressing the start button  166 .  
         [0109]     The following commonly owned U.S. patents and U.S. patent applications are related to the present application and are incorporated herein by reference in their entirety: U.S. Pat. No. 6,969,399 entitled “APPARATUS FOR ALTERING THE BODY TEMPERATURE OF A PATIENT”; U.S. patent application Ser. No. 10/896,506, filed on Jul. 22, 2004 entitled “APPARATUS FOR ALTERING THE BODY TEMPERATURE OF A PATIENT”; U.S. patent application Ser. No. 10/950,152, filed on Sep. 24, 2004 entitled “APPARATUS FOR ALTERING THE BODY TEMPERATURE OF A PATIENT”; and U.S. patent application Ser. No. 10/948,918, filed on Sep. 24, 2004 entitled “APPARATUS FOR ALTERING THE BODY TEMPERATURE OF A PATIENT”.  
         [0110]     In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.  
         [0111]     When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.  
         [0112]     As various changes could be made in the above without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.