Patent Application
20080221493
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, while allowing decompression of the patient's torso.
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.
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.
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.
To this end, apparatus, such as that disclosed in U.S. patent application Ser. No. 11/466,955, filed Aug. 24, 2006, which is incorporated by reference in its entirety, has been provided to lower the temperature of the patient. The apparatus disclosed in the '955 application is amenable to traditional CPR methods. However, more advanced CPR methods may potentially be needed for some patients to provide sufficient circulation for effective cooling.
One known method of advanced CPR for producing higher circulation rates as compared to conventional CPR is Phased Thoracic Abdominal Compression-Decompression CPR. Phased Thoracic Abdominal Compression-Decompression CPR is administered to a patient by first compressing the patient's abdomen while decompressing the patient's chest, next the patient's chest is compressed while the patient's abdomen is decompressed, and lastly the patient is allowed to briefly rest to allow the heart to fill with blood. These steps are repeated as necessary.
There is need therefore for an apparatus that allows administering of advanced CPR while actively altering the temperature of the patient without adversely affecting the rate at which the patient's temperature is altered.
In one aspect, apparatus for altering the body temperature of a patient and administering decompression to a patient's torso generally comprises an upper member for overlying the patient's torso. The upper member has at least one inlet for directing heat transfer liquid into direct liquid contact with the patient's torso to promote heat transfer between the patient's torso and the heat transfer liquid. A decompression device is adapted for securement to the upper member for use in at least decompressing the patient's torso with the upper member interposed between the decompression device and the patient's torso. The upper member is configured to facilitate decompression of the patient's torso upon operation of the decompression device to apply a decompressive pressure to the upper member.
In another aspect, apparatus for altering the body temperature of a patient and administering decompression to a patient's torso generally comprises an upper member for placement above the patient's torso. The upper member has laterally opposite sides and a longitudinally extending opening located between the laterally opposite sides. The opening is configured for allowing access to a sternum of the patient when the upper member is placed above the patient. A lower member for placement beneath the patient's torso has laterally opposite sides that are releasable engageable with the laterally opposite sides of the upper member to form an interior space for receiving the patient's torso. At least one inlet is for directing heat transfer liquid into the interior space for direct liquid contact with the patient's torso to promote heat transfer between the patient's torso and the heat transfer liquid. At least one outlet is in fluid communication with the interior space for exhausting the heat transfer liquid from the enclosure.
In yet another aspect, a method for controlling the body temperature of a patient while administering decompressions to a torso of a patient generally comprises covering at least the torso of the patient's body with an upper member having a fluid passage therein and an opening in fluid communication with the passage. A heat transfer liquid is directed to flow within the passage of the upper member and out the opening for direct liquid contact with the patient's body to promote heat transfer between the heat transfer liquid and the patient's body. At least a sternum of the patient is decompressed simultaneous with the directing step.
Corresponding reference characters indicate corresponding parts throughout the drawings.
Referring now to the drawings and particularly to
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.
As illustrated in
As illustrated in
With reference to
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.
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's body. Specifically, the illustrated cover 22 is configured to distribute heat transfer liquid 18 over the patient P from the neck downward (see,
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 (
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's body received in the enclosure 14 (
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
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.
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's body, such as those more amenable to heat transfer (e.g., the head, neck, torso), than other non-selected portions of the patient's body, which are also received in the enclosure 14.
As illustrated in
In one suitable embodiment, the first and second plates 37, 39 are formed from a semi-rigid material, e.g., a semi-rigid plastic. As explained below, the first and second plates 37, 39 facilitate administering cyclical compressive forces to the patient's sternum and abdomen during active compression-decompression cardiopulmonary resuscitation or phased thoracic abdominal compression-decompression cardiopulmonary resuscitation. Particularly, the first and second plates 37, 39 are sufficiently rigid to transfer force to the patient during compression of the patient's sternum and abdomen by a compressive force applied to the cover 22 from outside the cover. It is contemplated that the plates 37, 39 could be rigid or formed from materials other than plastic (e.g., rubber, metal). It is also contemplated that the apparatus 10 can be configured for administering only decompression forces to the patient. That is, the apparatus 10 is not configured for administering compressive forces to the patient. In such an arrangement, the first and second plates 37, 39 may be of a different configuration or omitted from the cover.
In one suitable embodiment and as illustrated in
It is also contemplated that the first and second plates 37, 39 can be placed between the outer component 30 and the body-facing component 28 of the cover 22 with the outer component and body-facing component being bonded together around the periphery of the plates to thereby capture the plates between the components. It is further contemplated that the first and second plates 37, 39 can be formed integrally with either the outer component 30 or the body-facing component 28. The body-facing component 28 may have other configurations than that illustrated in
The passages 32 in the cover 22 for delivering heat transfer liquid 18 to the patient P received in the enclosure 14 suitably surround the first and second plates 37, 39. In the illustrated embodiment, three such passages 32 surround each of the plates 37, 39 but it is understood that more or fewer passages can be used. As a result, heat transfer liquid 18 can be effectively delivered to portions of the patient's torso covered by the first and second plates 37, 39. Moreover, the passages 32 surrounding the first and second plates 37, 39 can be used to facilitate administering decompressive forces to the patient's sternum and abdomen as explained below.
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.
With reference now to
The stacked inflatable tubes 44A, 44B 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 44A, 44B in a deflated state. The base 42 and inflatable tubes 44A, 44B are then inflated to enclose the patient's body within the well 46 and generally conform the well to the profile of the patient's body. As the inflatable tubes 44A, 44B 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 44A, 44B. As a result, the base 42 easily conforms to the contours of the patient P because of the patient'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's body (
With reference to
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.
As illustrated in
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. 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.
With reference to
The paired first and second components 56A, 56B forming the lower tube 44B are overlaid by the paired third and fourth components 56C, 56D forming the upper tube 44A and sealed together. More specifically and with reference to
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 56D (
With reference to
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 (
Referring now to
With reference again to
The forth component 56D 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 56A-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. It is understood that the support for underlying the patient P may have other constructions then that disclosed herein including being a non-compliant support.
Referring to
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.
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 (
The weir dam 87 is located in a weir housing 88 and cooperates with the weir housing to selectively retard the flow of heat transfer liquid 18. As illustrated in
The handle 90 can be used to selectively move the weir 86 between a flow restricting position (
As illustrated in
As shown in
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.
Referring now to
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.
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.
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 (
The illustrated reservoir 112 comprises a plastic bag removably supported in the mobile cart by a frame 124 with handles (
As illustrated in
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's body.
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's body, or both (i.e., simultaneously over the top of the patient's body and underneath the patient'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 10 liters per minute (2.6 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 8 liters per minute (2.1 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 18 liters per minute (4.7 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.
The pumps 114 described above were specifically designed gear pumps for use in this apparatus 10 (
Both of the pumps 114 incorporate detachable pumpheads (not shown) that are contained in the pumphead housing 140 (
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 (
The pressure sensors 144, which are shown in
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 44A, 44B 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 compliant support 24.
Referring to
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 (
In the illustrated configuration, the second coupling members 160B are affixed to the ends of the umbilicus 120 (
The apparatus 10 shown in the attached drawings is intended to be used a medical treatment facility (e.g., a hospital) or in an ambulance on the way to a medical treatment facility. 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 (
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'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'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.
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.
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'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.
The amount of time necessary to induce hypothermia in a patient P is dependent on numerous factors including how much of the patient'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's body. As a result, the enclosure 14 is adapted to enclose substantially the entire body of the patient's thereby providing a large portion of the patient'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.
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'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).
As illustrated in
The patient facing surface 206 of the board 202 includes an adhesive (not shown) for adhering the decompression device 200 to the cover 22 or, as explained below, directly to the patient P. In one suitable use, the decompression device 200 is adhered to the cover 22 so that the narrow portion 202A of the board is aligned with and covers the first plate 37 of the cover and the passages 32 surrounding the first plate (
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
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 44A, 44B, 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 44A, 44B 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 44A, 44B 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.
The cover 22 is placed on the patient P to cover the patient's body from the neck downward. The first plate 37 of the cover 22 is generally aligned with the sternum of the patient P and the second plate 39 is generally aligned with the abdomen of the patient. 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
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 liquid 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 liquid fill line 130 (see
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'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
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.
With both pumps 114 operating, the heat transfer liquid 18 directly contacts the body of the patient P at a flow rate of about 18 liters per minute (4.7 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.
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.
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's temperature reaches or approaches the selected temperature. The patient'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's temperature drops to the selected temperature to prevent overshoot (i.e., lowering the patient'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'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.
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 (
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.
The inflatable tubes 44A, 44B, 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 (
If necessary and at any point during the operation of the apparatus 10, active compression-decompression cardiopulmonary resuscitation or phased thoracic abdominal compression-decompression cardiopulmonary resuscitation 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. More specifically, the decompression device 200 is adhered (or otherwise secured) to the outer surface 30 of the cover 22 by a user (e.g., a doctor, nurse, EMT) such that the narrow portion 202A of the board 202 overlies the first plate 37 and the broad portion 202B of the board overlies the second plate 39.
The user grasps each of the handles 208 and applies a compressive force to the sternum of the patient P by pushing downward on the handle mounted to the narrow portion 202A of the board 202 thereby causing the first plate 37 of the cover 22 to engage and press against the sternum of the patient (
Oxygen is drawn into the patient's lungs and blood is drawn into the patient's heart during the pause and the decompression of the patient's sternum and compression of the patient's abdomen. Oxygen is forced from the patient's lungs and blood is forced from the patient's heart during compression of the patient's sternum and decompression of the patient's heart. Thus, this cyclical and repetitive motion fosters blood and oxygen flow throughout the patient's body. Some of the benefits of blood and oxygen flow, such as organ preservation, are apparent. However, the flow of the blood and oxygen throughout the patient's body also facilitates cooling of the patient. Blood and oxygen near the skin of the body are cooled by the direct contact between the skin and the heat transfer liquid 18 and then flow throughout the patient's body, including the patient's brain and core (i.e., the patient's thorax) thereby causing the patient to cool more rapidly than if blood and oxygen were not flowing throughout the patient's body.
The passages 32 in the cover 22 surrounding the first and second plates 37, 39 facilitate the decompressions of the sternum and abdomen of the patient P. During decompressions, the user lifts or pulls upward on the handles 208 of the decompression device 200 thereby applying an upward force on the portion of the cover 22 which is connected to the board 202. The heat transfer liquid 18 and the passages 32 surrounding the plates 37, 39 cooperatively create a seal between the cover 22 and the patient's skin thereby transferring the upward force to the patient's sternum or abdomen. In another suitable embodiment, the heat transfer liquid 18 and/or air can be drawn through the openings 36 in the passages 32 surrounding the first and second plate 37, 39 to create a vacuum seal between the patient's skin and the cover 22. In yet another suitable embodiment, adhesive can be applied to either the patient P or the cover 22 to create a seal between the patient's skin and the cover. It is understood that the seal between the patient's skin and cover 22 can be formed in any suitable way without departing from the scope of an aspect of this invention.
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'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' operations can occur in the ambulance on route to the medical facility thereby not delaying any subsequent medical care.
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.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
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.
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.
This application claims the benefit of U.S. Provisional Application No. 60/868,968, filed Dec. 7, 2006, which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60868968 | Dec 2006 | US |
