System And Method For Determining And Controlling Core Body Temperature

Abstract

Systems and methods for accurate temperature modification of a patient, or selected regions thereof, including inducing hypothermia. The temperature modification is accomplished using an in-dwelling heat exchange catheter within which a fluid heat exchange medium circulates. A heat exchange cassette attached to the circulatory flow lines of the catheter, the heat exchange cassette being sized to engage a cavity within a control unit. A temperature measurement scheme for obtaining body core temperature is provided, including methods of obtaining and analyzing temperature data to provide feedback to the control unit for use in controlling the heating and cooling of the heat exchange medium so as to heat or cool a patient to a desired target temperature.

1 - 41 . (canceled) 
     
     
         42 . A system for controlling the temperature of a patient to achieve a target temperature of the patient's body, comprising:
 a heat transfer catheter insertable into a patient;   a heat exchange unit having a fluid pathway therewithin;   conduits coupled to the heat transfer catheter and heat exchange unit to enable circulation of a heat exchange medium therebetween;   a fluid flow control device operable to alter the fluid pathway to bypass the heat transfer catheter;   a heater/cooler in thermal conduction with the fluid pathway;   a processor configured
 to receive a target body temperature input from an input device and a sensor signal from a temperature sensor, the temperature signal representative of the temperature of the patient's body, 
 to analyze the signal from the sensor while the fluid flow is altered to determine a rate of change of the temperature as a function of time, 
 to compare the determined temperature to a target temperature, 
 to control the fluid flow control device to alter fluid circulation within the heat exchange unit and the heat transfer catheter, and 
 to control the rate at which the patient temperature approaches the target temperature by controlling the heater/cooler to add or remove thermal energy from the heat exchange medium. 
   
     
     
         43 . The system of  claim 42 , wherein the fluid flow control device is a diverter valve activated by the controller. 
     
     
         44 . The system of  claim 42 , wherein the fluid flow control device is a flow actuated valve. 
     
     
         45 . The system of  claim 42 , wherein the heater/cooler comprises a thermoelectric heater/cooler, 
     
     
         46 . The system of  claim 42 , further including a plurality of sensors supplying patient data to the processor, the processor being configured to operate the heater/cooler based on the supplied patient data. 
     
     
         47 . The controller of  claim 46  wherein the processor is responsive to each of the sensors to control the heater/cooler.