Method and system for control of a patient's body temperature by way of a transluminally insertable heat exchange catheter

Abstract

Methods and apparatuses for temperature modification of a patient, or selected regions thereof, including an induced state of 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 of any one of several disclosed variations is attached to the circulatory conduits of the catheter, the heat exchange cassette being sized to engage a cavity within one of various described re-usable control units. The control units include a heater/cooler device, a user input device, and a processor connected to receive input from various sensors around the body and the system. The heater/cooler device may be thermoelectric to enable both heating and 15″ cooling based on polarity. A temperature control scheme for ramping the body temperature up or down without overshoot is provided. The disposable heat exchange cassettes may include an integral pump head that engages with a pump drive mechanism within the re-usable control unit. More than one control unit may be provided to receive the same heat exchange cassette so that, for example, a large capacity control unit can be used initially, and a smaller, battery-powered unit can be substituted once the patient reaches the desired target temperature.

1 - 36 . (canceled) 
     
     
         37 . A method of regulating the temperature of at least a portion of a patient, comprising:
 providing a disposable heat transfer catheter having a heat transfer region and a heat exchange unit having a pump head, the heat transfer catheter and heat exchange unit coupled via conduits that enable circulation of a heat exchange medium therebetween;   providing a master control unit housing a heater/cool unit within and having a slot;   installing the heat exchange unit through the slot into the master control unit and into thermal communication with the heater/cooler unit;   inserting the heat transfer catheter into the patient;   sensing the patient's body temperature;   selecting a target temperature different than the body temperature;   circulating fluid between the heat transfer catheter and heat exchange unit in the master control unit, the heat exchange unit, heater/cooler unit, and pump head being adapted to flow heat exchange medium through the conduits to elevate or depress the temperature of the catheter heat transfer region relative to the body temperature; and   transferring heat between the heat exchange unit and a heater/cooler unit so as to regulate the temperature of the patient via the heat transfer catheter;   selecting a ramp rate equal to the time rate of change of temperature from the body temperature to the target temperature;   monitoring the temperature differential between the target temperature and the body temperature; and   reducing the ramp rate when the temperature differential reduces below a predetermined threshold.   
     
     
         38 . The method of  claim 37 , wherein the disposable heat exchange unit includes a serpentine pathway through which the heat exchange medium flows, and circulating includes circulating the heat exchange medium back and forth through the serpentine pathway. 
     
     
         39 . The method of  claim 37 , wherein the disposable heat exchange unit incorporates a fluid pathway and an integral pump head, and circulating includes driving the pump head. 
     
     
         40 . The method of  claim 37 , wherein the master control unit houses a pump driver, and installing includes engaging the pump driver with the pump head. 
     
     
         41 . The method of  claim 37 , wherein the heater/cooler unit comprises a thermoelectric heater/cooler, and transferring comprises either heating or cooling the temperature of the patient based on the polarity that the thermoelectric heater/cooler is operated.