Patent ID: 7666215

Claim:
A method for measuring body temperature while regulating the temperature of at least a portion of a patient using a heat exchange catheter inserted into a lumen of the patient's body, the heat exchange catheter having conduits that enable circulation of a heat exchange medium between a heat exchange portion of the catheter and a heating/cooling apparatus for adding or removing thermal energy from the heat exchange fluid, the heating/cooling apparatus controlled by a controller, comprising: providing a temperature probe to measure the temperature of the fluid circulating through the lumen of the patient's body, the temperature probe providing a signal representative of the temperature of the fluid circulating through the lumen of the patient's body to the controller; circulating fluid under control of the controller between the heat transfer catheter and the heating/cooling apparatus; stopping the flow of heat exchange medium through the heat exchange catheter for a selected period of time; analyzing the signals received from the temperature probe while the flow of heat exchange medium is stopped and determining an estimated temperature of the fluid circulating through the lumen of the patient's body from the rate of change of the temperature while the flow of heat exchange medium is stopped; comparing the determined temperature to a target temperature; re-starting the flow of heat exchange medium through the heat transfer catheter; and controlling the heating/cooling apparatus in accordance with the comparison to controllably add or remove thermal energy from the heat exchange fluid to heat or cool the fluid circulating through the lumen of the patient's body to heat or cool the fluid circulating through the lumen of the patient's body to the target temperature.