CZ20003216A3 - System and method for heat control of a living body - Google Patents

Abstract

The body temperature control system (BCT) is made with a heat exchanger, in particular in the form of a garment (220), for transferring heat to a part of the body's surface or for removing heat from these parts, and at least one sensing element a real temperature measurement device (aBCT) and pro transmitting a data signal characterizing this actual signal temperature (aBCT) of the individual to the control device (94) and pro transmitting a control signal to control the properties of the exchanger heat exchange as a function of data signals a the desired temperature (dBCT) of the body surface. System it comprises at least one additional sensor for measuring a parameter indicating the body surface temperature of the subject for determining the heat transfer rate (HDT) parameter between the body surface and the body and the body issuing dynamics data signal (HDT) heat transfer to the control device (94).

Description

Technical field

The present invention relates to a system and method of thermoregulation of a living body. The system and method of the present invention can be applied to humans and other animals.

BACKGROUND OF THE INVENTION

The living body is normally able to maintain a normal body temperature of 36.5-37 ° C. However, if the body is exposed to extreme temperature conditions or a variety of drugs, the body temperature may not be properly controlled. This occurs, for example, in individuals exposed to extreme temperatures and in a variety of diseases and conditions (such as general anesthesia) where the body loses its ability to properly regulate body temperature.

Hypothermia means a decrease in body temperature, which can occur, for example, by exposure to a cold environment. Mild hypothermia, in which the core body temperature (especially the temperature of internal organs and tissues in the body) is lowered by about 2 ° C below normal temperature, commonly occurs during and after surgeries performed under general anesthesia, as patients tend to lose body heat due to decreased metabolism and exposure to internal body organs and tissues, e.g., in the abdominal or thoracic cavity, at ambient temperature.

Hypothermia occurs in more than 60% of patients after surgery. In some surgical procedures, such as open-heart surgery, hypothermia occurs in more than 90% of adults.

Hypothermia can cause various severe physiological problems including heart disease, coagulopathy, impaired immune function, impaired wound healing, tremor, impaired pharmacokinetic properties of drugs, etc.

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Hyperthermia, especially elevation of body temperature above normal levels, can cause various physiological diseases and, if extreme, can be life-threatening.

For a long time, there is a known clinical need for a body temperature control device.

MicroClimate Systems Inc., Stanford, MI, USA, has launched a series of portable personal refrigeration systems (sold under the trademarks Koolvest, Kooljacket, Koolband, Koolpaid and others), designed for healthy people performing physical activity in a hot environment (see http://www.microclimate.com/prodline.html or http://www.microclimate.com/work.html). The system consists of clothing (which can be a vest, coat, headgear, neck collar, etc.) with a built-in duct through which water runs through the battery pump. Water flows through ice or cooling equipment before entering the pipeline in the garment. The user can regulate pump operation, temperature, etc. A similar product line is also provided by Mallinckrodt Inc. St. Louis, MO, U.S.A. (see Internet http: //www/mallinckrodt.com/ccd) as well as other companies.

A similar system is also disclosed in U.S. Pat. No. 4807447 (Mmacdonald et al.). A unique feature of this system is that the refrigeration compressor operates on the basis of a person's breathing.

Various systems based on the use of clothing, cushions or blankets with heat transfer elements, such as built-in piping, are disclosed in U.S. Pat. Patents 3738367, 4094357, 4094367, 4149541, 4844072, 5184612 and 5269369. However, due to various physiological reasons that only follow from the present invention and which will be further specified, none of the above systems provides adequate control of the body temperature of individuals in general and patients in particular. surgery before general anesthesia.

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Also in veterinary medicine there is a need for body temperature control, especially body temperature control during surgical procedures under general anesthesia. Animals, especially small animals, occasionally die during surgery due to uncontrolled changes in body temperature.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, the term core temperature will be used to denote body temperature, particularly internal organ and tissue temperatures. The core temperature is typically measured rectally (rectal temperature measurement), but can also be measured by inserting probes into a variety of other body cavities, eg, probes for measuring the temperature in the oral, nasal, or ear cavity. The term surface temperature will be used to denote the temperature of the outer body surface (which may be the skin, or the outer layer in the case of absence of the skin, for example, in burns). It should be noted that the surface temperature may vary between different parts of the body. The surface temperature can be measured using a variety of temperature probes including, for example, an infrared sensor measuring infrared radiation from a specific portion of the skin, probes attached to the skin, such as thermal devices, thermistors, etc.

In accordance with the present invention, it has been found that the main drawback of the prior art thermoregulatory devices is that they do not sufficiently align the fact that the body is not a passive heat conductor, but rather uses internal dynamic physiological thermoregulatory mechanisms that can change heat transfer between the body core and peripheral. For example, after exposure to low temperature, vasoconstriction of peripheral blood vessels occurs, thereby reducing blood flow to the periphery and thereby reducing heat transfer between the periphery and the body core. In other situations, vasodilatation results in increased blood flow to the periphery, resulting in increased heat transfer between the body core and the periphery.

In accordance with the present invention there is provided a system and method for controlling body temperature. The system and method of the invention allow controlled cooling of the body, controlled heating, as well as controlling body temperature to maintain the desired set point. A unique feature of the invention is that it takes into account the complexity of heat transfer from the skin to the body core. This complexity is manifested by dynamic heat transfer, particularly by physiological changes that disrupt the degree of heat transfer between the skin and body core. This heat transfer dynamics (HTD) can be determined in a number of ways, as further illustrated below.

In accordance with the present invention, a body core temperature control (BCT) system is provided comprising:

- heat exchanger for heat transfer or heat removal of body surface parts /

- at least one body core temperature sensing device for measuring the actual body core temperature (aBCT) and transmitting the aBCT data signal;

- at least one sensing device for measuring heat transfer dynamics (HTD) parameters between the body surface and the body core and for transmitting an HTD data signal; and

- a control module for registering data signals from measuring devices consisting of aBCT and HTD data signals, and for transmitting a control signal for controlling the heat exchange of said heat exchanger as a function of the desired body core temperature (dBCT) data signals.

The heat exchange may be provided by an internal heating or cooling device including, for example, Peltier effect modules, or the heat exchanger may be connected to at least one source of cold and / or hot liquid, which then circulates between that source and the heat exchanger, thereby transferring heat between the exchanger and said source.

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In another aspect, the present invention provides a method for controlling the internal body temperature, comprising the steps of:

a) defining a desired body core temperature (dBCT);

(b) providing a heat exchanger and mediating contact between the heat exchanger and at least a portion of the external surface of the body for the purpose of transferring or removing heat from a portion of the body;

c) continuously measuring parameters including at least the actual body core temperature (aBCT) and a parameter indicating the heat transfer dynamics (HTD) between the body surface and the core; and

d) registering data signals by a processor corresponding to the measured parameters, further comparing aBCT with dBCT, determining the need for heating or cooling, and sending a control signal controlling the heat transfer through said heat exchanger based on the aBCT / dBCT difference and said HTD.

Checking the heat exchange properties of said heat exchanger may include changing the heat transfer properties between the heat exchanger and the body surface, which may be. achieved, for example, by changing the thermal conductivity parameters between the body surface and the skin, for example by pumping or removing air from the air pockets positioned between the heat radiating and absorbing elements between the heat exchanger and the skin, or preferably by changing the heat exchanger temperature, either by reducing the heating or cooling range; heating or cooling, or by varying heating or cooling while cooling or heating, respectively. In this change, the heat exchanger operating first as the heat source is switched to function as a heat sink or more versa, thus reversing the direction of heat transfer.

For example, the heat exchanger may consist of an electric heating / cooling device, such as a Peltier device or the like. However, in accordance with a preferred, non-limiting embodiment of the invention, the heat exchanger is formed by one or more tubing or a liquid transfer medium to allow the flow of the thermal control liquid and to transfer or absorb heat.

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9 9 9 9 9 'from the body surface. A liquid, which is typically, but not exclusively, a liquid, such as water, may flow through the tubing or medium through a pump or other suitable device. This fluid is circulated between the heat exchanger and the heat source and / or cold. The heat exchanger is typically flexible to allow close contact with the body surface for efficient heat transfer.

In addition to the aforementioned measuring devices (BCT sensing devices and measuring devices for said HTD), the system may further comprise one or more devices measuring the temperature of the circulating liquid and transmitting the respective data signal to the monitoring device. In the case where the system is comprised of two or more devices, at least one may serve as a device for sensing the inlet temperature of the liquid entering the at least one tube or liquid transfer medium, and at least one other may serve as a device for sensing the outlet temperature of the liquid exiting from the at least one tube. or a liquid transfer medium. The temperature drop (delta T) between the inlet and outlet of the garment is a very good indicator of said HTD, since this information together with the fluid flow information allows an accurate calculation of the heat transfer between the heat exchanger and the body, which depends on said HTD. Therefore, in accordance with a preferred embodiment of the invention, said delta T and liquid flow are used as HTD parameters.

The heat exchanger object of the invention is typically a garment that wears part of an individual's body. The garment typically covers at least 30%, preferably at least 40% of the body surface. In this way, the system object of the invention effectively stabilizes, with a minimum tolerance, the body temperature of an individual to the desired body core temperature. Such garments may be in various forms depending on the desired use. For example, the garment may be designed for use in individuals performing heavy work under extremely high temperature conditions to cool their body. For this purpose, the garment must be relatively flexible to minimize the free movement of the individual. The garment can also be a 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9 Designed for medical use, either to reduce body core temperature in individuals with very high fever diseases, to increase body core temperature in individuals in hypothermia, or both. A current preferred embodiment of the invention is the application of a system for controlling the body temperature of patients during or after general anesthesia. For this purpose, the heat exchanger, typically in the form of a garment, may have a variety of apertures allowing access to perform various surgical procedures, for parenteral administration of drugs or fluids, or for drainage of body fluids (eg excretions or blood).

One example of the use of the system and method of the present invention is, in accordance with the above-mentioned embodiment, open heart surgery. These procedures typically lower the body temperature to about 32 ° C. During such surgery, heart activity is temporarily stopped and blood circulates through the extracorporeal circulation. After such an operation, it is necessary to raise the body temperature as quickly as possible to a normal value, as prolonged lowering of the body core temperature may harm the patient, and even endanger his or her life. According to current medical practice, at the end of surgery, blood is heated during circulation through extracorporeal circulation. However, this procedure is inadequate because the body core is not sufficiently heated, and as soon as the extracorporeal circulation is disconnected and the blood is recirculated through the reactivated heart, the blood temperature decreases. Heating after these procedures is typically done today by using warm blankets, blowing hot air on the individual, etc. In summary, the methods available today do not allow effective monitoring and control of body core temperature. In accordance with the invention, the body core temperature can be controlled lowered during the initial phase of the surgery, then maintained at about 32 ° C by heating or cooling as needed, and finally controlled increased to the normal body temperature at the end of the procedure.

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The system and method of the invention can generally be used to control the patient's body temperature at a perioperative time in a variety of surgical operations.

It will be appreciated that the heat exchanger in the form of a garment may typically be designed in various forms and sizes to meet the specifications of individuals of different ages, weights, regimens, etc., or specific requirements of specific medical procedures.

In addition to human use, particularly in human medicine, the method and system of the present invention may find application in a variety of veterinary applications. The same problems with maintaining normal body temperature, as well as with controlled cooling during surgical procedures, also occur in veterinary medicine. As will be appreciated, the heat exchanger can typically be in the form of a mat, blanket or garment, designed in various shapes, depending on the type of animal, type of surgery, etc.

The system of the present invention intended for use in an operating room can typically be designed to allow data exchange with other operating room devices. These include, for example, importing data relating to extracorporeal blood temperature, cardiac rhythm or blood pressure data from appropriate measuring devices, etc.

A sensing device for measuring skin parameters corresponding to said HTD (hereinafter referred to as the HTD device) may, in accordance with one embodiment of the invention, include an apparatus for measuring the temperature of the skin portion proximal to the skin portion on which the heat exchanger is placed. The HTD can then be determined, for example, in one or both of the following ways:

5) determining a temperature change on said skin part after heating or cooling adjacent skin parts using a heat exchanger; or

6) assessing the change in temperature difference between the skin part and the core during heating or cooling the body.

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Said HTD device may, in accordance with another embodiment of the invention, comprise the aforementioned at least two sensing devices for measuring the temperature of the liquid entering the at least one heat exchanger tube and the temperature that exits the at least one tube. The control device then registers at least two data signals relating to the measured temperature, then calculates said HTD based on the difference in temperature of the inlet and outlet, which is determined either by the controls or measured by the respective measuring device.

In accordance with other embodiments of the invention, said HTD device is adapted to measure said HTD, which parameter may be one of a variety of skin and peripheral blood flow parameters. These parameters can be determined using a variety of techniques, for example, techniques to measure echo doppler signal, skin conductivity, blood peripheral pressure, skin temperature, skin color, etc.

One of the main features of the invention relates to measuring said heat transfer dynamics (HTD) and incorporating this dynamics into the overall assessment of an individual's heat control regime. Specifically, if HTD parameters indicate the occurrence of vasoconstriction, the applied cooling should be temporarily stopped or reduced. Sometimes it is also advantageous to reverse the heat transfer method, that is, to heat up temporarily even when cooling is set. That is, the cooling method comprises intermittent heat pulses timed and adapted to said HTD.

The system may have a user interface allowing the user to adjust the dBCT, particularly the system temperature setpoint. The user interface may further comprise control means allowing the selective operation of the system either in an automatic manner, in particular in a manner allowing both cooling and heating depending on the direction and deviation of aBCT from dBCT. In addition, the control means may also typically allow only heating or cooling to be selected.

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Heating is typically limited so that the surface temperature of the heat exchanger in contact with the body surface does not exceed a maximum temperature, eg, about 40 ° C, and does not fall below a minimum temperature, eg, about 15 ° C.

In order to achieve efficient cooling or heating, the heat exchanger, typically in the form of a garment, must be affixed to the skin of the individual. Occasionally it may be necessary to wear the garment for an extended period of time and this can cause bruising. To avoid this problem, the heat exchanger has two or more individual flow control subsystems in accordance with one embodiment of the present invention. These subsystems can be used intermittently, especially when one system is filled with fluid and used while the other is empty and does not exert pressure on the skin; and more versa. In accordance with another embodiment of the invention, the transfer of fluid to the garment is temporarily stopped for a few seconds to minutes to reduce the pressure on the skin, thereby reducing the pressure.

In accordance with one embodiment of the invention, the system consists of an electric in-line liquid heating / cooling unit and the circulation of the liquid is conducted through said heating or cooling unit. The heating or cooling of the liquid in this unit can be achieved by means of an auxiliary circulating liquid to transfer heat through the intermediate portion of the heat exchanger in said unit. In accordance with another embodiment of the invention, the system comprises at least one cold liquid reservoir and at least one hot liquid reservoir and comprises a liquid flow control system for selectively directing liquid from these reservoirs. One of the advantages of independent reservoirs of hot and cold liquid is that switching between heating and cooling can be quickly achieved.

In a system consisting of independent reservoirs of hot and cold liquid, the flow control system is preferably adapted to allow the liquid to return to the reservoir from where the liquid

J • · comes. It is preferred that during switching between cold and hot liquid or vice versa, the original liquid flows first to the reservoir from where it originates and only after the hot liquid is utilized is directed to the second reservoir upon its return. The cold reservoir may be heated and the hot reservoir may be cooled. This can be achieved with a liquid temperature sensing device flowing through the heat exchanger, and only if the device measures a rapid temperature change does the flow control system direct the liquid to a new reservoir.

In order to understand the invention and to see how it can be used in practice, a preferred embodiment of the invention will now be described by way of non-limiting example with occasional reference to the accompanying drawings:

SORTED — PICTURE DESCRIPTION:

In FIG. 1A shows a garment in accordance with an embodiment of the invention.

In FIG. 1B shows an enlargement of the region indicated in FIG. 1A letter B with two outer layers partially separated for illustrative purposes.

In FIG. 1B is a top view of an open laid garment for use in a system in accordance with an embodiment of the invention.

In FIG. 3 is a schematic illustration of the garment of FIG. 1 applied to the patient.

In FIG. 4 is a side view of the patient in the garment of FIG. 3. In FIG. 5 shows the garment in accordance with another embodiment of the invention in an open state with a patient lying on the garment provided with an adhesive mass.

In FIG. 6 is a schematic general illustration of a system in accordance with the invention.

In FIG. 7 is a schematic side view of the system of FIG. 6.

In FIG. 8 is a schematic illustration of a system in accordance with another embodiment of the invention.

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In FIG. 9A and 9B is a schematic block diagram of an algorithm that operates in a system in accordance with one embodiment of the invention. (Fig. 9B is a continuation of Fig. 9A).

DETAILED DESCRIPTION OF THE PRESENT FORMS OF THE INVENTION

In FIG. 1A is a top view of an open-garment garment 2 in accordance with one embodiment of the invention. The garment 2 is designed to be attached to a person's torso. The garment 2, which can be seen specifically in FIG. 1B is formed by two outer layers 4 and 6, between which space 7 is defined, through which the liquid flows. The garment comprises a liquid inlet 8 and a liquid outlet 10 entering and exiting the liquid flow space. The garment has a baffle 12 which defines a liquid pathway schematically represented by the arrow 14. The liquid is typically water, but may be any other suitable liquid, e.g., alcohol, oil, etc., and may also be in other embodiments of the invention. gas, for example air.

As further seen in FIG. 1B, the garment comprises a matrix of soldered dots 16 wherein two outer layers 4 and 6 of the garment 2 are soldered together. When the garment is used, the fluid pushes the two layers apart and fills the space between the soldered points. The soldered points provide the structural integrity of the two layers and further provide a certain resistance to the liquid flow and consequently a significantly uniform distribution of the liquid throughout the liquid flow compartment 7 of the garment. As will be appreciated, the inner structure of the garment is merely an example. In other embodiments of the invention, the garment may be formed by two outer layers forming a sandwich with a porous matrix therein, it may comprise tubes or other conduits lowered or defined by soldered lines, etc.

The top view of the garment, in accordance with another embodiment of the invention, is shown in an open configuration and generally indicated by 20 as seen in FIG. 2. The garment 20 has apertures 22 and 24 which, when the garment is mounted on a person, allows access to a portion of the skin stored beneath the garment, for example, to measure the temperature of the skin. , for injection, etc. Rather than the apertures 22 and 24, the garment may also be provided with flaps for a similar purpose. The garment is provided with a plurality of notches 28, 30 and 32 for attaching the garment to an individual's body, as can be seen in Figs. A garment that may have a similar internal structure to that shown in FIG. 1B, it is formed by soldered lines 34A, 34B, 35, 36A, and 36B that together define a fluid flow path represented by arrows 37A, 37B, 37C, and 37D extending from the liquid inlet 44 and the liquid outlet 46. In this case, the garment has a structure such that the chest and abdomen of the individual are left free, making the garment suitable for thoracic and abdominal surgery. For other surgical applications, the garment may have a variety of other different shapes. In addition, the garment may be provided in different sizes to fit individuals of different weight, sex, age, etc.

The garment may be comprised of a variety of different materials including fabric, plastics, etc. The garment should preferably be elastic and elastic to fit the body of the individual. The outer fabric layer may be coated with a heat insulating material to prevent heat transfer to the external environment. In addition, the garment may have a soft inner lining, such as a felt, to prevent pressure sores.

Further, the garment, as will be explained with reference to FIG. 5, provided with an inner liquid-absorbing layer.

The garment may be made reusable or may be made occasionally disposable. Reusable garments should be made of materials that allow sterilization by any of a variety of known sterilization techniques.

As seen in Figures 2-4, the fluid inlet and outlet tubes 44 and 46 are connectable to the fluid temperature monitoring unit 48 (shown in Figure 4).

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To be easy to attach and remove, the garment is typically provided with detachable attachment means, such as Velcro ™ based fasteners (e.g., Velcro ™).

Fig. 5 is a planar view of the garment 120 in accordance with another embodiment of the invention in an open position prior to attachment to a patient's body. In this figure, similar reference numerals are used as in Figures 2-4 with an index of 100 (particularly prefix 1) and the reader is referred to the description of Figures 2-4 for explanation. As further seen in FIG. 5, the die 50 is made of an absorbent material. Typically, the matrix has a liquid permeable layer and contains a hygroscopic material capable of absorbing and retaining liquids therein. Such matrices with liquid-absorbing properties are well known in the art and a detailed description of their structure goes beyond the scope of this application.

In FIG. Also shown in Figure 5 are skin temperature probes 60 and 62 and a rectal temperature probe 64. In addition, other types of temperature measuring devices may be used, such as an inner ear temperature measuring device, an infrared skin temperature measuring device, a mouth temperature measuring device for measuring core temperature, etc. As explained above, the skin temperature is measured in accordance with one. form of the invention to determine the heat transfer dynamics (HTD) of the skin. For the same purpose, as an alternative to skin temperature measurement, other parameters may be measured, including skin color, skin conductivity, peripheral blood pressure, drop in heating or cooling fluid temperature (as will also be discussed below), as well as other parameters which may indicate the occurrence of vasoconstriction or vasodilation.

In addition, temperature sensing devices 70 and 72 may be advantageously provided for measuring the temperature of the inlet and outlet fluids. This information may also be used to determine the degree of heat transfer between the heat exchanger, in particular clothing, and the skin, in order to assess the HTD.

Figures 6 and 7 show a scheme of the system in accordance with another embodiment of the invention. Patient 80 is provided with garment 220 (shown schematically in Figure 5 as a rectangle). In Figures 6 and 7, the same reference numerals are used as before, with only an index of 200. The garment 220 is provided with a liquid inlet 244 and a liquid outlet 246 with a continuous liquid duct or a continuous porous space 240 therebetween incorporated in the garment 220. a number of sensing devices shown schematically as component 90 herein transmit data signals reflecting the physiological parameters of the patient to the control device 94.

The system of this embodiment is adapted to both heat and cool the patient. In one embodiment, both hot and cold liquid are provided from respective independent hot and cold liquid reservoirs 96 and 98. Each of these reservoirs has respective inlets 101, 102 and respective liquid outlets 103, 104. The system is equipped with a pump 105 for driving the fluid through the system.

The system is equipped with two flow control valves 106 and 107 for selectively transferring returning or pumped liquid from one of the two reservoirs. The pump 105 and the flow control valves 106 and 107 are supplied with power by the monitoring device 94 via control cables 108, 109 and 110.

If heating is switched to cooling, or more versa, the flow control valves are switched accordingly. In accordance with one embodiment of the invention, the liquid outlet 246 is provided with a temperature sensor 272 that allows the return of the liquid from one reservoir to another only by rapid temperature change registered by the sensing device 272, which then transmits a data signal to the monitoring device. ··· · ··· -L Ό · «· · ·

94, which then causes the flow control valve to switch. The arrangement is such that the first flow control valve to be switched is valve 107, and if, for example, the switch was from cold to hot liquid, valve 106 continues to direct the returning liquid to reservoir 102 and only by registering a sharp temperature drop by sensor 272 the returning liquid is directed to the reservoir 96.

In other embodiments of the invention, as shown in FIG. 8, the heating and cooling of the working fluid is performed on-line by a heat pump operating as a heating / cooling unit. This unit, which may for example be equipped with Peltier effect heat pumps, may be more easily controlled to heat or cool the liquid passing through the unit.

In FIG. 8 shows a schematic description of a system in accordance with an embodiment of the invention. Here again, as used in the description above, the index "300" is used, and the reader is referred to the previous description to explain its function. The control device 394 is equipped with a display 311 to display the registered parameters, such as measured core temperature, measured skin temperature, desired core temperature, flow, liquid temperature, etc. The control device is additionally equipped with a control panel 312 and a processor 313. all sensing devices (core temperature measuring device 364, skin temperature measuring device 362, optional infrared-based skin temperature measuring device 314, and others). In addition, the processor also obtains temperature data from the inlet and outlet fluid temperature sensing devices 370 and 372, and the temperature data registered by the heating / cooling device 315 via the sensor 316. For example, the device 315 may be a known Peltier effect heat pump. In addition, the control device controls the flow of the pump 308 via the control cable 317 and controls the temperature of the device 315 via the cable 318.

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Based on the different data signals registered by the processor and using various algorithms designed in accordance with the general principle of the invention, such as below, the fluid flow and / or its temperature can be controlled. Various servo loops may be used via processor 313 to properly check the various parameters.

In FIG. 8, an algorithm of various calculated steps of an algorithm used in a processor in accordance with an embodiment of the invention is shown by means of a box diagram. In contrast to the preceding figures, the reference numerals used in this figure have no relation to the previously mentioned reference numerals.

In the first decision step 410, the system is started and its integrity checked. If the system detects an error in any of its components, the system shutdown sequence 412 is triggered. In the initial step different operating methods are set. These can be automatic, or perform only heating or cooling only.

Other parameters that can be set by the user include the minimum and maximum allowable temperature of the heat transfer fluid, typically water, to prevent tissue damage as well as to avoid discomfort to the patient, especially when not under general anesthesia.

In the next two decision steps 414 and 416, the actual water temperature (indicated as WATER TEMPERATURE) is compared with the maximum allowable water temperature (HIGH TEMPERATURE) and the minimum allowable water temperature (LOW TEMPERATURE).

In step 414, if the water temperature is higher than the HIGH TEMP limit, the cooling sequence 418 is started, and if in step 416 the water temperature is too low, the heating sequence 420 is started.

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In the next decision step 422, the operating method is selected based on user input, either cooling only, heating only, or automatic, indicated by 424, 426 and 428.

In the first heating step decision step 430, the core temperature (CORE TEMPERATURE) is compared with the desired set core body temperature (SETTING VALUE). If the body core temperature is above the set value, the system is instructed to switch to the backup method 432, in particular the heating function is stopped. During the backup mode function, the core temperature is continuously measured and compared to the set value.

If the core body temperature is found to be below the set point, the water temperature is compared to the high temperature at 434 and if the water temperature is lower than the high temperature, the heating method 420 is started. If the water temperature is found to be above the high temperature. , the system is again instructed to switch to the backup method 432.

In the first decision step 440 of the cooling method 424, the core temperature is compared to a set value. If the core body temperature is below the set point, the system is instructed to switch to the backup mode 432. If the core body temperature is below the set point, the system determines whether there is a vasoconstriction of the skin 442. If the vasoconstriction has not occurred, decision step 444 in which the water temperature is compared to the minimum allowable temperature. If the water temperature is lower than the LOW TEMPERATURE, the system is instructed to switch to the backup mode 432, and if it is above this temperature, the cooling sequence 418 is initiated.

If it is determined in step 442 that vasoconstriction has occurred (i.e.

low conductivity between the core and the periphery is detected) despite the fact that the cooling process is in progress, the heating sequence is triggered. If the vasoconstriction is found to have subsided, cooling is resumed.

In the first decision step 450 of the automatic method 428, the core temperature is compared to a set value. If the core body temperature is below the set value, the system is instructed to switch to the heating method 426. If the core body temperature is below the set value, the sequence proceeds to the next decision step 452 and here, if the core temperature is above the set value, If the core temperature is below the set value, the system is switched to the backup mode.

In the algorithm described above, the only parameter checked is the water temperature. It should be understood that in other embodiments, other parameters, such as the flow rate of the heat transfer fluid, can also be controlled. In addition, various other parameters, such as blood temperature, can also be incorporated in the system output, for example based on data imported from the extracorporeal circulation.

As will be appreciated, the determination of the occurrence of vasoconstriction may be based on a variety of parameters, as mentioned above, using data obtained from one or more of the above-described sensing devices.

Claims (24)

PATENT CLAIMS A temperature control system (BCT) of an individual's body core, having a heat exchanger for transferring heat to a portion of an individual's body surface or dissipating heat from a portion of an individual's body surface, with at least one individual temperature sensing device (aBCT) and transmitting a data signal characterizing this actual temperature (aBCT) of the individual, with a control device (94, 394) for receiving data signals comprising a data signal characterizing the actual temperature (aBCT) of the individual and transmitting a control signal to control the heat exchanger properties signals and a desired body surface temperature (dBCT) of the subject, comprising at least one additional sensing device for measuring a parameter indicative of the subject's body surface temperature to determine a parameter indicative of heat transfer dynamics (HTD) between the subject's body surface, and temperature (BCT) of the individual ' s core and for outputting a data signal characterizing the heat transfer dynamics (HTD) to the control device (94, 394). The system of claim 1, wherein the heat exchanger comprises one or more heat control fluid passage tubes for transferring heat to the body surface of the individual or for absorbing heat from the body surface of the individual. System according to claim 2, characterized in that the heat exchanger is connected to a device for circulating the heat-regulating fluid through the tubes. · * * 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 999 99 99 System according to claim 2 or 3, characterized in that it comprises one or more sensing devices (272, 370, 372) for measuring the temperature of the circulating fluid and for transmitting a data signal characterizing it to the control device (94, 394). . System according to one of claims 2 to 4, characterized in that the fluid is a liquid. System according to one of the preceding claims, characterized in that the heat exchanger comprises a garment (20, 120, 220, 320) intended to be worn on a part of the body. System according to one of the preceding claims for use in regulating a patient's body temperature during or after general anesthesia or during the perioperative period. System according to claim 7, characterized in that the heat exchanger comprises a garment (20, 120, 220, 320) intended to be worn on part of the body. The system of claim 8, wherein the garment (20) has apertures (22, 24) to allow access for surgery, parenteral administration, or fluid drainage. The system of claim 7 or 8, wherein at least a portion of the garment (20) is provided with a removable and resilient matrix (50) of liquid absorbent absorbent material. System according to one of the preceding claims, characterized in that the sensing device for measuring the heat transfer dynamics (HTD) parameter comprises a device for: 99 9 9 9 9 999 9 9 9 9 999 99 Measuring the temperature of the skin portion proximal to the skin portion to which the heat exchanger is applied, wherein the determination of the heat transfer dynamics (HTD) is based on the rate of temperature change. System according to one of claims 1 to 10, characterized in that the sensing device for measuring the skin parameter comprises a device for measuring the temperature of the skin portion proximal to the skin portion to which the heat exchanger is applied, wherein determining the heat transfer dynamics (HTD) it is based on the rate of change in the temperature difference between the skin part and the body core. System according to claim 4 or 5, characterized in that it comprises at least one sensing device (370) for measuring the inlet temperature of the fluid entering the at least one tube and at least one sensing device (372) for measuring the fluid outlet temperature of the at least one tube, the sensing devices (370, 372) being coupled to a control device (394) for transmitting the respective data to the control device (394) for calculating the heat transfer dynamics (HTD) by the control device (394) based on the temperature difference between the inlet and outlet temperature and fluid flow. System according to one of the preceding claims, characterized in that the surface parameter is a parameter selected from the group consisting of a body surface temperature parameter, skin color, skin peripheral blood pressure, skin electrical voltage, skin conductivity, doppler echo signal. System according to one of the preceding claims, characterized in that during heating or cooling the heating or cooling function is temporarily stopped or changed to cooling or heating. • · · · • · * * * «« «* * * * System according to claim 15, characterized in that the stop or change to heating or cooling is performed automatically if the determined heat transfer dynamics (HTD) indicate a reduction in heat transfer between the periphery and the body core, i.e. the occurrence of vasoconstriction. System according to one of the preceding claims, characterized in that the control device (94, 394) has a cooling operation mode, a heating operation mode and an automatic operation mode for automatic heating or cooling depending on the difference between the core temperature and the desired core temperature. System according to one of the preceding claims, characterized in that it comprises a user control interface for enabling the user to set a desired body surface temperature (dBCT) or to set the system to operate in cooling, warm-up, or automatic mode. System according to one of the preceding claims, characterized in that the temperature of the heat exchanger is maintained between a minimum and a maximum temperature to prevent tissue damage with respect to its exposure to excessive heating or cooling. System according to one of the preceding claims, characterized in that the heat exchanger is provided with at least two individual subsystems with individual flow control. System according to one of claims 2 to 5, characterized in that it comprises at least one electrical unit for heating / cooling the fluid, the fluid being rectified for flow through the electrical unit. System according to one of claims 2 to 5, characterized in that it comprises at least one cold fluid reservoir (98) and at least one hot fluid reservoir (96) and a control system for controlling fluid flow for selectively draining fluid from the reservoirs (98). 96). System according to claim 22, characterized in that the control system for regulating the fluid flow allows the fluid to be returned to the reservoir (96, 98) from which the fluid is drained. System according to claim 22 or 23, characterized in that it comprises at least one sensing device for measuring the temperature of the fluid flowing out of the heat exchanger and changing the fluid withdrawal from the reservoir (96, 98) for draining the fluid from the second reservoir (98, 96 ) the fluid flow control system initially directs the returning fluid to one reservoir (96, 98), and when the sensing device senses a substantial temperature change, it directs the returning fluid to the other reservoir (98, 96).