MXPA00000401A - An inflatable thermal blanket for convectively and evaporatively cooling a body - Google Patents

Abstract

An inflatable thermal blanket is disclosed for convectively and evaporatively cooling a patient. The inflatable thermal blanket comprises an upper sheet and a base sheet that are attached at a plurality of locations to form an inflatable covering. The base sheet includes a plurality of apertures that direct an inflating medium from the inflatable covering toward the patient. The base sheet also supports a fluid delivery apparatus that distributes and delivers a cooling fluid to the patient. The fluid is evaporated from the patient's skin by the inflating medium exhausted from the inflatable covering. The fluid delivery apparatus may be constructed in a variety of configurations and may be circulate a variety of fluids, which may be pressurized or unpressurized. In operation, an air blower, that may also include a compressor for selectively delivering room temperature or cooled air to the inflatable thermal blanket, is connected to the inflatable covering. The blower delivers air, under pressure, to an inlet opening in the inflatable covering. The pressurized air is distributed throughout the inflatable covering and flows to the patient through the apertures in the base sheet. The inflatable thermal blanket is configured to cover one or more portions of a patient's body. In one construction, the inflatable thermal blanket covers all of the patient's body except for the head. In an alternative construction, a specially designed inflatable thermal blanket is constructed to cover only the patient's head.

Description

I? FLABLE THERMAL BLANKET TO COOL A BODY BY CONVECTION AND EVAPORATION TECHNICAL FIELD The present invention relates generally to blankets used in medical equipment, to provide a bath of a thermally controlled gaseous medium, such as air, to a patient.

ANTECEDENTS OF THE TECHNIQUE The thermal blanket of the prior art is described in commonly assigned US Patent No. 4,572,188, entitled "AIR FLOW COVER FOR CONTROLLING BODY TEMPERATURE" and in US Patent No. 5,405,371 entitled "THERMAL BLANKET". These two Patents describe thermal blankets that include a plurality of inflatable chambers that communicate. In these blankets, the openings are formed through the base sheets of the blanket. These openings are communicated to the cameras through the base sheets. When inflated with hot air, the air pressure in the chambers causes the air flow cover to inflate. The openings draw hot air through the base sheets and hot air is contained between the base sheets and the patients. Therefore, these thermal blankets create an environment on the patient, whose thermal characteristics are determined by the temperature and pressure of the gaseous medium of inflation.

Temperature control in humans has important medical consequences. The human body has evolved over several million years, to keep its marrow temperature within a narrow range. Thermoregulatory responses, such as vasoconstriction, vasodilatation, chills or sweating, occur as a reaction to changes in the temperature of the marrow body as small as +/- 0.1 ° C. Human cell functions, biochemical reactions and enzymatic reactions are optimized within this narrow range of temperature.

The thermal blankets of the prior art address the heating problem of a patient in order to treat hypothermia (a lower than normal marrow temperature), as it may occur during an operative or postoperative process. These thermal blankets have proven to be extremely useful and efficient in the treatment of patients whose spinal cord temperatures could otherwise become undesirably low, either during or after a medical procedure, such as surgery.

However, there are circumstances under which a patient should cool instead of warm up, in order to treat hyperthermia (a marrow temperature higher than normal). Hyperthermia can be the result of stress or strain or of a disease. Otherwise, normal individuals may suffer hyperthermia when their natural cooling mechanisms, such as sweating, become saturated during heavy physical work in a warm environment. This is generally associated with a relatively inadequate fluid intake, which results in inappropriate sweating. Stress or heat stress disorders, in a category in ascending order of severity, include cramps, syncopes, exhaustion and attacks, by heat. Normally, a person will voluntarily suspend work before heat exhaustion occurs, but competing athletes or military personnel can go beyond this limit.

Hyperthermia can also result from a fever associated with a disease. This fever has many causes, which include: an infection, tumor necrosis, thyroid attack, malignant hyperthermia or brain injury. The brain lesions that cause hyperthermia, by general 1Q involve the hypothalamus and can be caused by tumors, attacks, head injuries or ischemic brain injury due to cardiac arrest.

The physiological consequences of hyperthermia extend in a spectrum of severity with electrolyte and fluid imbalances, increased cellular metabolic velocities and cognitive deterioration in the minor degree. In the middle spectrum, impairment of motor skills, loss of consciousness and attacks occur. At the highest end, the individual suffers irreversible brain damage, especially from highly metabolic liver and brain cells and then the organ deteriorates and dies. Hyperthermia is, in this way, a condition that, depending on its severity, may require an immediate cooling treatment to return the temperature of the patient's marrow to normal.

The cooling treatment can also have other important uses. There is growing evidence suggesting that in some situations, mild to moderate hypothermia can provide a beneficial protection against injury. The protective benefit of hypothermia has been shown when the blood flow of part or all of the brain is interrupted. Cerebral ischemia due to an interruption of blood flow can occur during cardiac arrest, surgery in the blood vessels of the brain, an attack, traumatic brain injury or open heart surgery. Cooling the brain before or, in some cases, after this happens, turns out to be a protection and decreases the severity of the final brain damage.

For centuries, various devices and techniques have been used to cool the human body. The categories of cooling technologies can be, generally: by conduction, by convection or by evaporation. While many techniques have been tried, all are limited in the clinical team because they lack practicality, due to their difficulty of use, their ineffectiveness and / or excessive energy consumption.

Cooling by conduction is very effective when it is carried out by encapsulating a hyperthermic person on ice or submerging in ice or cold water. Although ice is an effective cooling medium, it causes pain to the patient, can damage the skin, is often not available in large quantities and its use for large periods is not practical. Water baths are also effective, however, they are not practical for the comatose or intensive care patient or for large periods of time. A method of cooling by conduction, less effective but commonly used, involves placing the person in and / or under a mattress and / or cold water circulation cover. These devices have cameras through which water circulates. The water cools the surfaces of the device, which in turn removes the patient's heat as long as the surfaces make thermal contact with the patient's skin. These devices are usually uncomfortable and heavy and their thermal contact is often inefficient, because they are not configured precisely on the body surface.

Convection cooling consists of directing air at room temperature or air cooled to the patient.

Convection cooling is the least effective cooling method from a thermodynamic point of view. The air at room temperature can be directed very economically with a fan. However, the effectiveness in cooling is severely limited if the patient is not sweating. The air can be cooled with a traditional compression system or with a pump air conditioner that heats it or by means of thermoelectric cooling. The cooled air has also been generated for centuries using the principle called * saturation cooler "of water vaporization in the air stream.The water evaporates in the air, thus cooling the air.Afterwards the cooled air is applied to the person. .

In US Patent No. 5,497,633 entitled "EVAPORATION COOLING UNIT" by Jones et al, an example of such a cooler is shown.After the air has been cooled by any of these techniques, a person can be carried off by generally cooling the surrounding air, such as cooling the air in a room For more efficient convection cooling that uses less energy, cold air can be brought to the person more effectively, confining cooling only to the person. using a convective thermal blanket such as that shown in the aforementioned US Patents No. 4,572,188 or 5,405,371 and incorporated herein by reference.Another convective thermal blanket is shown in US Patent No. 4,777,802 entitled "SELECTIVELY ADJUSTABLE BLANKET AND APPARATUS ASSEMBLY". PROVIDE COOLING OR AIR HEATING "by Feher. Confined convective cooling has also been shown in the form of a jacket-like device in U.S. Patent No. 5,062,424, entitled "PORTABLE APPARATUS FOR REQUEST REDUCTION OF ELEVATED BODY MEDULATION TEMPERATURE" from Hooker.

Convection cooling removes the voltage from the hot environment, but is ineffective in active cooling. This limited thermodynamic efficiency is particularly evident when it comes to cooling patients with fever. Usually, in order to cool by convection, patients must be anesthetized and paralyzed to prevent the heat from producing chills. In addition, the thermodynamic inefficiency of the cooled by convection, causes this method of cooling to use considerable electrical energy and generate a significant residual heat, which can be a problem in the emergency or in an intensive care situation.

Evaporative cooling is the thermodynamic basis of the highly efficient sweating response. Each gram of water that evaporates, extracts 540 calories from the heat of the skin of the body that is cooling. Due to the high degree of heat of water vaporization, large amounts of body heat are removed by the evaporation of relatively small amounts of water. Cooling by evaporation has been practiced since the beginning of mankind, by simply wetting the skin or clothes and allowing the wetting agent to evaporate. Evaporative cooling is still used today in hospitals, in the form of sponge baths, where the patient is wetted with water and allowed to dry by evaporation. Sometimes a ventilator will be placed to give air to the patient and thus increase the rate of evaporation. While this cooling method is clearly effective, it is a very intense, complicated task, requiring the patient to be fully exposed and usually not practical for prolonged cooling. Finally, the effectiveness of evaporative cooling is severely limited in very humid environments.

Therefore, there is a need for a temperature control device and, in particular, a thermal blanket that can be adapted to a patient that requires hyperthermia treatment, or that needs a cooling as a mechanism for preventing injury. What is required is an economic cover that quickly cools a patient and that is efficient in a clinical team, and can also be easily and conveniently used by medical personnel.

DESCRIPTION OF THE INVENTION In accordance with certain objects of this invention and to overcome the limitations of the prior art, an apparatus is provided that combines evaporation with convection to cool a patient. The apparatus includes an inflatable thermal blanket with an upper sheet and a base sheet that are joined in a plurality of locations to form an inflatable structure. The base sheet includes a plurality of openings that discharge an inflation means of the inflatable structure towards the patient. An air fan or fan that may also include a compressor, to selectively deliver to the thermal blanket, cooled air or room temperature, which delivers air under pressure to an inlet opening in the inflatable thermal blanket. The pressurized air is distributed within the inflatable structure and flows towards the patient through the openings in the base sheet. The base sheet supports a fluid delivery element that directs a cooling fluid to the patient. The fluid is evaporated by the inflation medium that leaves the inflatable structure. The fluid delivery element can be constructed in a variety of configurations and can circulate a variety of fluids that may or may not be pressurized.

The inflatable thermal blanket is configured to cover one or more portions of the patient's body. In a first preferred development, the thermal blanket covers the entire body of the patient with the exception of the head. In an alternative development, a thermal blanket specially designed to cover only the patient's head is constructed.

Therefore, it is a main objective of the invention to provide adaptable, economical and effective means for rapidly cooling a body (human or animal).

A further object of the invention is to provide a device for cooling a body, both by convection and by evaporation.

Another object of the present invention is to provide such cooling in an inexpensive, inflatable thermal blanket that can be employed with existing inflatable thermal blanket equipment.

The above objects, aspects and advantages of the present invention, together with additional ones, will become more apparent when reference is made to the following specification, claims and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of this invention, reference is made to the following detailed description of its embodiments, as illustrated in the accompanying drawings, wherein: Figure 1 is a perspective view of a patient and an inflatable thermal blanket according to the invention, deployed with an air forced pump that supplies air to the thermal blanket and a fluid supply system to deliver a cooling fluid by evaporation to the thermal blanket.

Figure 2 is a partial cross-sectional view taken through an inflatable portion of the inflatable thermal blanket of Figure 1.

Figure 3 is a diagrammatic cross-sectional view of the patient and the inflatable thermal blanket of Figure 1, showing an alternative lateral placement arrangement for the components of a fluid delivery apparatus.

Figure 4 is another view is the diagrammatic cross section of the patient and the inflatable thermal blanket of Figure 1, showing another alternative lateral placement arrangement for the components of a fluid delivery apparatus.

Figure 5 is a bottom view of the inflatable thermal blanket of Figure 1, showing an alternative two-dimensional location for the components of a fluid delivery apparatus, also showing an alternative diversification.

Figure 6 is a bottom view of the inflatable thermal blanket of Figure 1, showing another alternative two-dimensional arrangement for the components of a fluid delivery apparatus and other alternative diversification.

Figure 7 is a bottom view of the inflatable thermal blanket of Figure 1, showing another alternative two-dimensional location for the components of a fluid delivery apparatus and other alternative diversification.

Figure 8 is another diagramatic cross-sectional view of the patient and the inflatable thermal blanket of Figure 1, showing additional components that can be used in the inflatable thermal blanket.

Figure 9 is a perspective view of a patient and an inflatable thermal blanket, also illustrating an air forced pump for supplying air to the inflatable thermal blanket and an alternative fluid supply apparatus for delivering an evaporative cooling fluid. to the inflatable thermal blanket.

Figure 10 is a side view of a patient and an inflatable thermal blanket, for convection and evaporation cooling of a patient's head.

Figure 11 is a side-cut view of the inflatable thermal blanket of Figure 10, showing its construction details.

Figure 12 is a sectional view of the patient and the inflatable thermal blanket of Figure 10, showing its additional construction details.

THE BEST WAY TO CARRY OUT THE INVENTION The present invention is represented by the developments established in the following description and in that illustrated in the figures, in which like numbers represent the same or similar elements. While the present invention is described in terms of an exemplary development, it will be apparent to those skilled in the art that variations may be made based on what has been taught herein, without deviating from the spirit or scope of the invention.

Effective cooling of the patient in a clinical team, is carried out by providing an inflatable thermal blanket that joins an air delivery system to provide a component of convection cooling, with a fluid delivery apparatus to provide an evaporative cooling component. It has been found that combining convection cooling with evaporative cooling with an inflatable thermal blanket dramatically increases the cooling effectiveness of convection cooling, while making evaporative cooling convenient and practical, even for extended use. . The inflatable thermal blankets described here maximize the positive aspects of convection and evaporation cooling, while minimizing the negative aspects of each one.

Figure 1 illustrates a patient 100 in a prone position on an examination or operating table 102. Table 102 may be in the doctor's office, in an external patient facility associated with a hospital facility or in any another suitable place. The patient 100 is illustrated with its head 104 and its shoulders 106 stretched and supported on the table 102 (together with the rest of the patient's body). As shown in Figures 3 and 4, the arms 110 of the patient lie on the sides thereof.

An inflatable thermal blanket designated with the reference number 120 and with components of cooling by convection and evaporation is shown, covering the whole body of the patient except for the head 104 and the shoulders 106. The inflatable thermal blanket 120 includes an inflatable section 130 surrounded by a non-inflatable section having a foot cover 140 and side edges 150. A head cover may also be provided, as well as one or more interruptions in the inflatable section 130, to facilitate unrestricted viewing of, and access to, , selected areas of the patient 100.

Moreover, Figure 1 does not mean limiting the invention to an inflatable thermal blanket that covers substantially the entire trunk and limbs of the patient. It can also be performed in an arrangement that uses an inflatable thermal blanket that is configured and deployed over portions of the patient's body, as well as over one or some of its extremities. In this regard, for example, reference is made to U.S. Patent No. 5,405,371, which describes inflatable thermal blankets covering the extended arms, upper chest and lower extremities of a person. In U.S. Patent Nos. 5,300,101; 5,324,320; 5,336,250 and; 5,350,417, other configurations are illustrated.

Returning to Figure 1, the inflatable section 130 includes an inlet 160 through which a temperature controller air flow is inflated to inflate the inflatable thermal blanket. The air flow is provided by an air hose 162 of an air forced unit 164. The air forced unit 164 includes at least one blower system driven by an electric motor or the like to deliver an air flow. The blower system preferably has a variable air speed control capacity and may have an air temperature control capability. Optionally, for an additional cooling effectiveness, especially in hot and humid environments, an air cooling or dehumidification unit could be included in the air forced unit. Alternatively, the air cooling or dehumidifying unit may be separated from the air forced unit, in which case it could be interposed between the air forced unit and the air hose 162. The cooled air increases the efficiency of the cooling component by convection of blanket 120. Dehumidified air increases the efficiency of the evaporative cooling component of the blanket. Therefore, the cooled and dehumidified air optimizes the cooling of the patient.

The inlet 160 of the inflatable section 130 can be provided with a fastener or other conventional connector adapted to receive and retain a nozzle 163 of the air hose 162. Using this configuration, the pressurized air can flow through the air hose 162. towards the inflatable section 130.

The inflatable thermal blanket 120 of this invention can be constructed by modifying a commercially available inflatable thermal blanket of the type known in the art, including BAIR HUGGER® thermal blankets from Augustine Medical, Inc., Eden Prairie MN. Alternatively, the inflatable thermal blanket 120 can be constructed using known methods and materials to make similar products. An example of construction details suitable for making the inflatable thermal blanket of this invention is found in commonly assigned U.S. Patent No. 5,405,371.

Referring now to Figures 1 and 2, the inflatable thermal blanket 120 is assembled from a base sheet 200 having a laminated structure in which a bottom layer 210 comprises a preferably non-woven fibrous structure composed of natural or synthetic materials. An upper layer 211 comprising a sheet of synthetic material is disposed in and laminated to a surface of the bottom layer 210. For example, the bottom layer 210 may be a hydroentangled, non-woven polyester material and the layer The upper can include a polypropylene film that is extruded to the polyester layer. According to a first alternative, the bottom layer 210 may comprise a non-woven paper-based material to which an upper layer including either polypropylene or polyethylene film has been laminated by glue. According to a second alternative, the bottom layer may comprise a single layer of fibrous material. To form an inflatable structure that can include one or more inflatable chambers 220, an upper sheet 215 is attached, in a plurality of locations, to the upper layer 211. Preferably, the upper sheet 215 comprises the same material as the upper layer 211 of the base sheet 200. In the preferred development, the upper sheet 215 is attached to the upper layer 211 in a continuous running fabric process, which includes stations in which the upper sheet 215 is heat bonded to the upper layer 211 for forming inflatable and non-inflatable sections of the inflatable thermal blanket 120. Inflatable chambers 220 are shown in Figures 1, 3 and 4 with a generally elongated tubular configuration, although said chambers and shapes are not necessary for the invention. The inflatable chambers 220 are formed by discontinuous elongated heat seals that extend longitudinally along the blanket 120. Figures 3 and 4 show a cross-sectional view of the elongated heat seals. These heat seals are shown with sealed portions 221 and unsealed portions 227. In the sealed portions 221 of the discontinuous elongate heat seals, the upper layer 211 of the base sheet 200 is attached to the upper sheet 215 in a waterproof elongated seam. in the air.

Where the discontinuities 227 occur, the air can circulate laterally between the inflatable chambers. These discontinuities provide communication between the inflatable chambers, allowing the pressurized air to circulate from the inlet 160 towards and through the inflatable chambers 220. It should be understood that the inflating structure may be formed by a plurality of seals or seals. lengthened The plurality of openings 217 that open through the base sheet 200, draw the pressurized air from the inflatable chambers 220 below the inflatable thermal blanket 120, to bathe the patient 100 in an atmosphere of cooling environment.

In Figures 1, 3 and 4, air-insensitive continuous seals 230 are shown along the sides of the inflatable thermal blanket 120. The continuous air-insensitive seals 232 and 234 also extend transversely at the ends of the air-tight seals. feet and the head of the blanket 120 respectively. These seals form one or more non-inflatable sections of the inflatable thermal blanket 150. These non-inflatable sections essentially function as covers that maintain an ambient atmosphere below the inflatable thermal blanket. As shown in Figures 1 and 3, there are two parallel, continuous, air insensitive edge seals 230, which are close to the respective sides of the inflatable thermal blanket and two continuous, air-insensitive end seals 232 and 234, in either end of the inflatable thermal blanket. Therefore, the perimeter of the inflatable thermal blanket 120 is sealed by a seal insensitive to continuous air, which comprises the seals 230, 232 and 234.

The invention further includes an evaporative cooling element comprising a fluid distribution apparatus 240. The fluid distribution apparatus 240 distributes fluid over, and delivers it to, various areas, portions or limbs of a patient's body. The fluid distribution apparatus 240 includes one or more fluid delivery channels or channels 250, mounted by the underside of the base sheet 200. Preferably, the conduits 250 are attached to the inflatable thermal blanket 120 in areas of the blanket which correspond to the areas of the patient's body that will be cooled by evaporation. In Figure 1, conduits 250 are shown extending from the patient's chest area to the patient's legs. In Figure 3, the conduits 250 are attached to the underside of the inflatable thermal blanket 120, below the central portions of the inflatable section 130. In Figure 4, the conduits 250 are attached to the underside of the thermal blanket. inflatable 120, under the elongated and discontinuous heat seals. An example of a fluid conduit would be a PVC pipe approximately 0.317 cm in internal diameter, similar to a standard IV (intravenous) pipe.

The fluid conduits 250 deliver fluid to the patient 100 through a plurality of orifices 252 that are intermittently formed along the length of each conduit in their walls. The holes 252 allow the fluid to be delivered to the selected area or areas of the patient 100. As shown in Figure 3, the holes 252 may be holes or openings or any other type of perforations that allow fluid to pass through the wall of the ducts 250 and be deposited below the surface of the body. Alternatively, as shown in Figure 4, the holes may be formed as nozzles 254 that allow fluid to be sprayed through ducts 250, below the surface of the body. Additionally, the holes 252 may include openings 256 at the ends of the conduits 250.

As shown in Figure 1, the fluid dispensing apparatus 240 includes a fluid container 260, connected to the conduits 250 via an inlet line 262 and an inlet manifold 264. The fluid container 260 is preferably a bag of fluid. Foldable plastic identical to IV fluid containers currently employed. Alternatively, a bottled fluid or a continuous supply of a water system may be used. The inlet line 262 is preferably made of a fluid supply line, such as a standard IV line with Luer connectors at each end. A valve 266 is provided in the inlet line 262, to allow an operator to control the flow velocity of the fluid. The input manifold 264 that distributes fluid between the conduits can be formed in various ways.

Figure 5 illustrates the input diversifier as a Y-connection copy 270 that is attached on its upstream side, to the end of the input line 262. Figure 5 also illustrates an alternative path for the ducts 250, in the that two ducts 272 and 274 made of a small orifice plastic pipe, are attached to the downstream side of the copy 270. These ducts extend from the upper side of the inflatable thermal blanket 120, to the underside thereof, through the respective holes 276 and 278 that are formed in adjacent ones of the seals that join the upper and base sheets of the inflatable thermal blanket 120. The conduits 272 and 274 are attached to the underside of the inflatable thermal blanket 120 in a coil path. In the configuration shown in Figure 5, the orifices 280 of the conduits are oriented to wet the entire body of the patient 100, except the area of the head. It should be understood that the ducts may be oriented to wet only selected parts of the body. As shown in Figure 5, the numerous air openings 217 will direct evaporative air to all portions of the patient's body where fluid is delivered through the conduits.

Figure 6 is an alternative construction for an inlet diversifier and fluid conduits. In this construction, the input diversifier is a linear section of tube 290 mounted on the underside of the blanket 120. The inlet line 262 extends through an orifice formed in a seal and is joined to a coupler 292 which is centrally located in the linear diversifier tube 290. Figure 6 also illustrates an alternative path for the conduits that deliver fluid for the evaporation. In the figure, five ducts 294, 295, 296, 297 and 298, made of a plastic or silicone pipe of small internal diameter, are joined at spaced locations in the linear diversifier tube 290. Each of these ducts is attached to the side from below the inflatable thermal blanket 120. Although the conduits are shown in a straight line trajectory, it should be understood that other trajectories may be used. In the configuration shown in Figure 6, the orifices 300 of the fluid distribution conduits are oriented to wet the entire body of the patient 100, except for the area of the head. It should also be understood that the conduits may be oriented to wet only selected parts of the body. As shown in Figure 6, numerous air openings 217 will direct evaporative air to all portions of the patient's body where fluid is delivered through the conduits.

Figure 7 illustrates another construction alternative for the inlet diversifier and fluid delivery conduits. In this construction, the inlet manifold is a central member 320 having a central fluid inlet and multiple radially oriented fluid outlets. The inlet line 262 extends through a hole formed in a central seal and is joined to a central inlet of the central member 320. Figure 7 also illustrates a path alternative for the conduits, in which eight conduits 322, 323 , 324, 325, 326, 327, 328 and 329 made of silicone tubing or small diameter plastic, are attached to the radial outlets of the central member 320. Each of these conduits is attached to the underside of the inflatable thermal blanket 120. In the configuration shown in Figure 7, the orifices 330 of the fluid distribution conduits are oriented to wet the entire body of the patient 100, except for the area of the head. It should also be understood that the conduits may be oriented to wet only selected parts of the body. As shown in Figure 7, the numerous air openings 217 will direct evaporation air to all portions of the patient's body where fluid is delivered through the conduits.

The Inventors contemplate modes of delivery of fluid different to the developments based on tubes that have been presented. For example, strips or sheets of hydrophilic material or wicking material could be used.

Preferably, the fluid dispensing apparatus delivers the cooling fluid by depositing it directly on the patient's skin 100. However, there may be times when direct application to the skin would be disadvantageous. For example, if the fluid flow rate is not adequately controlled, or if the contour of the patient's body allows spillage, some fluid may be poured under the patient. This fluid pooling is a waste, complicated and can damage the skin that remains in the puddled fluid for a prolonged period of time. Accordingly, as shown in Figure 8, a layer of wicking material 350 can be interposed freely between the underside of the inflatable thermal blanket 120 and its fluid distribution system and the skin of the patient 100. The Wick material 350 can be freely attached to the inflatable thermal blanket 120 by connecting only at the peripheral edges. The wicking material 350 can be any thin material, woven loose or non-woven. An example is a single layer of cotton gauze material. The wick material 350 serves to keep the fluid in the area of the skin where it is deposited, minimizing spillage.

If a low fluid supply pressure is desired, the fluid container 260 may be raised above the level of the inflatable thermal blanket 120, such that the fluid pressure is generated by gravity. This configuration is shown in Figure 1. If larger fluid supply pressures are desired, a pump 360 can be used as shown in Figure 9. The pump 360 is interposed in the fluid supply line 262. It can be provided using a of the many IV fluid pumps that are generally available. Other pumps can also be used. For example, the container 260 may be pressurized.

Preferably, the evaporation fluid used in the distribution system is water. However, other volatile fluids or mixtures with water can also be used. For example, in very humid environments, the cooling effect of evaporation is severely reduced. In these situations, it may be desired to use a different volatile fluid, such as a mixture of alcohol and water. Other non-toxic volatile fluids can be substituted or mixed with water to provide the desired evaporation characteristics. These fluid combinations may be pre-mixed and delivered in sealed containers for convenience or may be mixed by the therapy provider.

In addition to the inflatable thermal blankets configured for various combinations and partial portions of the extremities and trunk of the patient, special blanket configurations can also be constructed for various parts of the body. Figures 10, 11 and 12 illustrate an inflatable thermal blanket formed as a thermal helmet 400, constructed to fit over the head 402 of the patient 404. The helmet 400 is constructed in a manner similar to that of the inflatable thermal blanket 120. In this way, it has a base sheet 410 and an upper sheet 412, which are joined together by an air insensitive heat seal, continuous, in its periphery and, optionally attached to its inner portions with heat seals, to define an inflatable structure 414. The base sheet 410 is provided with a plurality of openings 416. The helmet 400 is inflated with the air delivered by an air hose 420. This air exits towards the head of the patient 402 through the openings 416. In this way, the helmet 400 has a component for cooling the patient 404 by convection. It also has an evaporation component that includes a conduit 430, made of plastic tube of small inner diameter or the like. The conduit 430 is attached to the underside of the helmet 400 and is arranged in the manner of a coil. The conduit 430 extends through a hole in the helmet 400 and is connected to the input line 432, via a connector 434. The input line 432 is connected to a fluid supply vessel (not shown) and delivers a cooling fluid to duct 430. Duct 430 is provided with multiple orifices 436, shown in Figure 12 as spray nozzles. Alternatively, holes or slots could also be used to provide the holes.

Advantageously, the regions of the patient's body that receive the combined convective and evaporative cooling according to the invention can be selected by the person who takes care of it. The volume of fluid delivered can be controlled either to completely evaporate or to be in excess and thus be delivered to body areas that are at different distances from the orifices. Optionally, a built-in liquid detector device can be employed to determine and control the delivery rate of fluid for evaporation.

The fluid distribution apparatus thus allows the fluid to be distributed and delivered to the desired portions of the patient's body, at a controlled rate, for a prolonged period of time, without requiring the inflatable thermal blanket to be left or frequent by the operator in charge. While the inflatable thermal blankets illustrated herein are shown in particular sizes and configurations, it will be recognized that, because the patients have different sizes and shapes, various shapes and sizes of inflatable thermal blankets may be available to accommodate most of the patients Other developments and modifications of this invention may be made, by experts in the field, from the teachings given herein. Therefore, the present invention is limited only by the following claims, which include all developments and modifications when viewed in conjunction with the description and the accompanying drawings.

Claims (21)

1. Apparatus for cooling a patient comprising: a top sheet (215) and a base sheet (200), connected together to a plurality of places, to form an inflatable cover (130) that includes: a first fluid inlet (160) ) to receive a first fluid in the inflatable cover and; a plurality of openings (217) extending through the base sheet, for letting the first fluid out of the inflatable cover; and characterized in that a fluid distribution apparatus 240 is adapted to deliver a second fluid, adjacent to the base sheet, the first and second fluids being different.

2. - The apparatus according to claim 1, wherein the fluid dispensing apparatus includes one or more conduits (250) having a plurality of holes (252) in said conduits.

3. - The apparatus according to claim 2, wherein the conduits comprise a plastic pipe.

4. - The apparatus according to claim 2, wherein the conduits comprise a silicone pipe.

5. - The apparatus according to claim 2, wherein the holes are holes in the conduits.

6. - The apparatus according to claim 2, wherein the holes are openings in the conduits.

7. - The apparatus according to claim 2, wherein the orifices are nozzles in the conduits.

8. - The apparatus according to claim 2, wherein the holes are holes in the ends of the conduits.

9. - The apparatus according to claim 2, wherein the fluid distribution apparatus includes a distribution diversifier (264) coupled with one or more conduits.

10. - The apparatus according to claim 2, further including at least one layer of wick material, adapted to be arranged adjacent to the fluid distribution apparatus.

11. - The apparatus according to claim 10, wherein the layer of wick material is made of a woven material.

12. - The apparatus according to claim 10, wherein the layer of wick material is made of non-woven material.

. 13. The apparatus according to claim 10, wherein the layer of wick material is freely attached to the inflatable thermal blanket.

14. - The apparatus according to claim 1, wherein the fluid dispensing apparatus is adapted to deliver a liquid adjacent to the base sheet.

15. Apparatus according to claim 1, further comprising: a first source of fluid (164).

16. - The apparatus according to claim 15, wherein the first fluid source is a temperature controlled air source.

17. - The apparatus according to claim 15, further comprising: a conduit coupling the first fluid source with the first fluid inlet (162).

18. - The apparatus according to claim 1, further comprising: a second source of fluid (260) in fluid communication with the fluid dispensing apparatus.

19. - The apparatus according to claim 18, wherein the second fluid source is a liquid container.

20. - The apparatus according to claim 18, further comprising: a pump (360), positioned between the second fluid source and the fluid distribution apparatus.

21. Apparatus according to claim 1, wherein the fluid delivery apparatus is adapted to deliver a second fluid, adjacent to a region of the base sheet that includes at least a portion of the openings.