System and method for determining and controlling core body temperature

A heat transfer catheter system for controlling the temperature of a patient to achieve a target temperature of the patient's body, comprising:

• a heat transfer catheter insert able into a patient;
• a heat exchange unit having a fluid pathway therewithin and incorporating an integral pump head adapted to move fluid through the fluid pathway;
• conduits coupled to the heat transfer catheter and heat exchange unit that enable circulation of a heat exchange medium therebetween upon operation of the pump head;
• a fluid flow control device that periodically redirects the fluid pathway, bypassing the heat transfer catheter;
• and
• a master control unit having a heater/cooler and a pump driver, the heat exchange unit being adapted to couple to the master control unit such that the pump driver engages the integral pump head so that the fluid pathway is in thermal communication with the heater/cooler, the master control unit controlling the fluid flow control device to periodically alter fluid circulation within the heat exchange unit and the heat transfer catheter, the master control unit 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 alter the flow of heat exchange medium through 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.