Catheter system for controlling a patient's body temperature by in situ blood temperature modification

A catheter system for controlling the temperature of at least a portion of the body of a patient by modifying the temperature of blood flowing within a blood vessel having a wall which defines a lumen of a first diameter, said catheter system comprising:

• a flexible catheter, said catheter being insertable into the blood vessel lumen, said catheter having a heat transfer region and a longitudinal axis, said heat transfer region comprising less than the entire length of the catheter and having a second diameter, the second diameter being smaller than the first diameter of the blood vessel lumen such that, when the system is in use, a space exists between the heat transfer region and the blood vessel wall, thereby allowing the temperature of blood to be modified as it flows past the heat exchange region of the catheter;
• a fin located on the heat transfer region of the catheter for increasing the surface area of the heat transfer region;
• a thermal conductor for transferring heat between the heat transfer region and blood flowing within the blood vessel lumen past the heat transfer region;
• temperature control apparatus comprising at least one of a) a heater and b) a cooler, for changing the temperature of the thermal conductor and thereby changing the amount of heat that is transferred to or from the patient's blood by the heat transfer region;
• and,
• sensing and control apparatus for preventing the heat transfer region from reaching temperatures that would substantially damage blood that flows through the blood vessel lumen past the heat transfer region.