Abstract: A catheter and method are provided for modifying a temperature of a patient. The catheter includes a heat transfer element (“HTE”) having surface irregularities shaped to create turbulence in a surrounding fluid. The catheter also includes a supply catheter to deliver a working fluid to an interior of the heat transfer element and a return catheter to return a working fluid from the HTE. A guidewire lumen is provided to receive a guidewire. The guidewire may have a temperature-monitoring device disposed at its distal tip from which feedback may be provided to control the temperature of a source of the working fluid.

Abstract: A method and apparatus for performing hypothermia of a selected organ without significant effect on surrounding organs or other tissues. A flexible catheter is inserted through the vascular system of a patient to place the distal tip of the catheter in an artery feeding the selected organ. A compressed refrigerant is pumped through the catheter to an expansion element near the distal tip of the catheter, where the refrigerant vaporizes and expands to cool a flexible heat transfer element in the distal tip of the catheter. The heat transfer element cools the blood flowing through the artery, to cool the selected organ, distal to the tip of the catheter.

Abstract: A method and apparatus for performing hypothermia of a selected organ without significant effect on surrounding organs or other tissues. A flexible catheter is inserted through the vascular system of a patient to place the distal tip of the catheter in an artery feeding the selected organ. A compressed refrigerant is pumped through the catheter to an expansion element near the distal tip of the catheter, where the refrigerant vaporizes and expands to cool a flexible bellows shaped heat transfer element in the distal tip of the catheter. The heat transfer bellows cools the blood flowing through the artery, to cool the selected organ, distal to the tip of the catheter.