Devices and Methods for Controlling a Subject's Body Temperature

Abstract

Devices and methods for controlling the operation of endovascular heat exchange devices and/or body surface heat exchange devices such as blankets.

What is claimed is: 
     
         1 . A controller device useable for controlling the operation of a body heat exchanger through which warmed or cooled fluid is circulated to exchange heat with all or a portion of the body of a human or animal subject, said controller device comprising:
 a processor which is connectable to a) a temperature sensor that senses a subject body temperature, b) a user interface through which a user may input a target subject body temperature and c) at least one heater-cooler for circulating heated or cooled heat exchange fluid through the body heat exchanger to alternately warm or cool the subject's body;   the processor being programmed to receive a target subject body temperature that has been entered via the user interface and indicia of the subject body temperature presently being sensed by the temperature sensor;   the processor being further programmed to cause said at least one heater-cooler to vary the temperature of heat exchange fluid being circulated through the body heat exchanger thereby controlling its addition of heat to, or removal of heat from, the subject's body as necessary to maintain the sensed temperature between an upper variance set point that is above the target subject body temperature and a lower variance set point that is below the target subject body temperature.   
     
     
         2 . A controller device according to  claim 1  wherein the processor is programmed to establish the upper variance set point and lower variance set point based on the input target body temperature that is received from the user interface. 
     
     
         3 . A controller device according to  claim 1  wherein the controller controls said at least one heater-cooler to i) maintain the body heat exchanger in an inactive state when the sensed body temperature is between the upper variance set point and lower variance set point, ii) cause the body heat exchanger to be in an active body heat removing state when the sensed temperature is greater than the upper variance set point and iii) cause the body heat exchanger to be in an active body heat adding state when the sensed body temperature is lower than the lower variance set point. 
     
     
         4 . A controller device according to  claim 1  wherein the controller is programmed to cause the body heat exchanger to initially warm or cool the subject's body until the target body temperature has been reached and, thereafter, to cause the body heat exchanger to neither add heat to nor remover heat from the subject's body until such time as the sensed body temperature falls below the lower variance set point or rises above the upper variance set point. 
     
     
         5 . A controller device according to  claim 1  configured to simultaneously receive sensed body temperatures from a plurality of separately located body temperature sensors and to independently vary the temperatures of a plurality of separately located body heat exchangers. 
     
     
         6 . A controller device according to  claim 1  that is connectable to and useable for controlling a body heat exchanger located on an endovascular catheter. 
     
     
         7 . A controller device according to  claim 1  that is connectable to and useable for controlling a body heat exchanger that is positionable on a surface of the subject's body. 
     
     
         8 . A controller device according to  claim 7  that is connectable to and useable for controlling a body heat exchanging blanket. 
     
     
         9 . A method for controlling a body temperature of a human or animal subject, said method comprising the steps of:
 positioning at least one temperature sensor on or in the subject's body to monitor a subject body temperature;   positioning at least one body heat exchanger on or in the subject's body;   connecting said at least one body heat exchanger to at least one heater-cooler which circulates heated or cooled thermal exchange fluid through said at least one body heat exchanger;   causing a controller, which comprises a processor, to communicate with said at least one temperature sensor and with said at least one heater-cooler such that the controller receives indicia of the sensed body temperature from said at least one temperature sensor and may issue control signals to the heater-cooler; and   inputting a target subject body temperature to the processor;   wherein the processor is programmed to cause the controller to issue control signals to the heater-cooler in response to the received indicia of sensed body temperature, thereby causing the sensed body temperature to increase or decrease to reach the target temperature and, thereafter, to maintain the sensed temperature between an upper variance set point that is above the target subject body temperature and a lower variance set point that is below the target subject body temperature.   
     
     
         10 . A method according to  claim 9  wherein the processor establishes the upper variance set point and lower variance set point based on the input target body temperature. 
     
     
         11 . A method according to  claim 9  wherein the controller controls the heater-cooler to i) maintain the body heat exchanger in an inactive state when the sensed body temperature is between the upper variance set point and lower variance set point, ii) cause the body heat exchanger to be in an active body heat removing state when the sensed temperature is greater than the upper variance set point and iii) cause the body heat exchanger to be in an active body heat adding state when the sensed body temperature is lower than the lower variance set point. 
     
     
         12 . A method according to  claim 9  wherein the controller is programmed to cause the body heat exchanger to initially warm or cool the subject's body until the target body temperature has been reached and, thereafter, to cause the body heat exchanger to neither add heat to nor remover heat from the subject's body until such time as the sensed body temperature falls below the lower variance set point or rises above the upper variance set point. 
     
     
         13 . A method according to  claim 9  wherein a plurality of body temperature sensors are positioned at a plurality of separate locations on or in the subject's body, a plurality of body heat exchangers are positioned at a plurality of separate sensor locations on or in the subject's body, a separate target temperature is input for each sensor location and the processor causes the controller to issue separate control signals to the plurality of body heat exchangers to cause each sensed body temperature to increase or decrease to reach the target temperature input for that sensor location and, thereafter, to maintain the sensed temperature at that sensor location between an upper variance set point that is above the target subject temperature input for that sensor location and a lower variance set point that is below the target subject body temperature input for that sensor location. 
     
     
         14 . A method according to  claim 9  wherein said at least one body heat exchanger is located on an endovascular catheter and wherein the method further comprises the step of inserting the endovascular catheter into the subject's vasculature so that said at least one body heat exchanger exchanges heat with the subject's blood. 
     
     
         15 . A method according to  claim 9  wherein said at least one body heat exchanger is positionable on a surface of the subject's body and wherein the method further comprises the step of positioning the body heat exchanger on a surface of the subject's body. 
     
     
         16 . A method according to  claim 15  wherein said at least one body heat exchanger comprises a blanket.