Method for Controlling a Patent's Body Temperature

Abstract

The present invention provides a method and apparatus for controlling the internal body temperature of a patient. According to the present invention, a catheter is inserted through an incision into a large blood vessel of a patient. By selectively heating or cooling a portion of the catheter lying within the blood vessel, heat may be transferred to or from blood flowing within the vessel and the patient's body temperature may thereby be increased or decreased as desired. The invention will find use in treating undesirable conditions of hypothermia and hyperthermia, or for inducing a condition of artificial hypothermia when desired.

1 . A method for altering the body temperature of a living patient having blood circulating through his or her vasculature, said method comprising the step of:
 A. providing a heat exchange catheter having a distal end which is insertable into the lumen of a blood vessel of the patient, a heat exchanger which occupies less than the entire length of the catheter, an inflow lumen through which a circulating heat exchange fluid flows into the heat exchanger and an outflow lumen through which the circulating heat exchange fluid flows out of the heat exchanger;   B. inserting the heat exchange catheter into the patient's vasculature with the heat exchange balloon in a deflated state;   C. advancing the catheter to a position where the heat exchange balloon is positioned within the blood vessel;   D. circulating heat exchange fluid through the heat exchanger without substantially impeding the flow of blood through the blood vessel and resulting in heat exchange between the circulating heat exchange fluid and blood flowing through the blood vessel; and   E. adjusting the temperature of the circulating heat exchange fluid to cause the patient's body temperature to be maintained at or changed to a desired body temperature.   
     
     
         2 . A method according to  claim 1  wherein the patient's body temperature is lowered. 
     
     
         3 . A method according to  claim 1  wherein the patient's body temperature is lowered below 37 degrees C. 
     
     
         4 . A method according to  claim 1  wherein the patient's body temperature is raised. 
     
     
         5 . A method according to  claim 1  wherein the patient's body temperature is lowered. 
     
     
         6 . A method according to  claim 5  wherein the patient's body temperature is temporarily lowered to a temperature that is sufficiently low to reduce the oxygen consumption of tissue within the patient's body. 
     
     
         7 . A method according to  claim 1  wherein the method is carried out to warm a patient who is hypothermic. 
     
     
         8 . A method according to  claim 1  wherein the method is carried out to cool a patient who is hyperthermic. 
     
     
         9 . A method according to  claim 1  wherein the heat exchanger has a blood contacting surface that is maintained within a range between about 20 degrees C. and about 24 degrees C. when cooling. 
     
     
         10 . A method according to  claim 1  wherein the heat exchanger has a blood contacting surface that is maintained below about 43 degrees C. when warming. 
     
     
         11 . A method according to  claim 1  wherein the distal end of the catheter remains within the patient's body during performance of Steps D and E. 
     
     
         12 . A method according to  claim 1  further comprising the step of:
 removing the catheter from the patient's vasculature. 
 
     
     
         13 . A method according to  claim 1  wherein the heat exchanger has a heat exchange surface that comprises at least one helical protrusion. 
     
     
         14 . A method according to  claim 13  wherein the helical protrusion on the heat exchange surface serves to increase the heat exchange surface area. 
     
     
         15 . A method according to  claim 1  wherein the heat exchanger expands when heat exchange fluid is circulated therethrough. 
     
     
         16 . A method according to  claim 1  further comprising the step of:
 monitoring patient body temperature. 
 
     
     
         17 . A method according to  claim 16  wherein the heat exchange catheter further comprises a temperature sensor and wherein the step of monitoring patient body temperature is carried out using that temperature sensor. 
     
     
         18 . A method according to claim  51  wherein the temperature sensor is located at the distal end of the catheter