Endovascular Cooling Catheter System Which Employs Phase-Changing Heat Exchange Media

Abstract

Devices and methods for cooling all or part of the body of a human or animal subject by inserting a heat exchange catheter into the subject's body and infusing into or through the catheter a heat exchange medium that contains liquid phase matter and frozen solid phase matter, wherein at least some of the solid phase matter melts while in the catheter.

1 . A system comprising:
 a heat exchange catheter or other body cooling device that is insertable into or positionable in contact with the body of a human or animal subject, said catheter or other body cooling device having an inlet, an outlet and at least one lumen through which heat exchange medium may be circulated;   a source of a heat exchange medium that comprises liquid phase matter and solid phase matter, wherein the solid phase matter has a melting point not higher than about 37 degrees C.; and   a pump or pressurization apparatus for circulating the heat exchange medium through the catheter while the catheter is inserted in the body of a human or animal subject;   wherein at least some of the solid phase matter melts thereby removing heat from the heat exchange medium.   
     
     
         2 . A system according to  claim 1  wherein the apparatus for delivering heat exchange medium comprises a pump or pressurization device connectable to the source of heat exchange medium. 
     
     
         3 . A system according to  claim 2  wherein the pump or pressurization device is connected to a vessel that contains a quantity of the heat exchange medium. 
     
     
         4 . A system according to  claim 1  wherein the heat exchange medium comprises a slurry. 
     
     
         5 . A system according to  claim 1  wherein the heat exchange medium is sterile. 
     
     
         6 . A system according to  claim 1  wherein the heat exchange medium is selected from the group consisting of:
 slurries comprising partially frozen saline solution; 
 slurries comprising partially frozen 0.9% aqueous NaCl solution; 
 
     
     
         7 . A system according to  claim 1  wherein the heat exchange medium contains from about 18% to about 50% solid phase matter. 
     
     
         8 . A system according to  claim 1  wherein the source of heat exchange medium comprises:
 a) a source of heat exchange medium concentrate; and 
 b) apparatus for diluting heat exchange medium concentrate to thereby form the heat exchange medium. 
 
     
     
         9 . A system according to  claim 8  wherein the apparatus for diluting comprises a pump or pressurization device that moves heat exchange medium concentrate from a vessel that contains the heat exchange medium concentrate to a location where the heat exchange concentrate becomes mixed with a liquid to form the heat exchange medium. 
     
     
         10 . A system according to  claim 9  wherein the pump or pressurization device comprises an upstream check valve, a downstream check valve, a compressible diaphragm and a ram that that repeatedly compresses and decompresses the diaphragm thereby causing the heat exchange medium concentrate to move through a conduit. 
     
     
         11 . A system according to  claim 8  wherein the heat exchange medium concentrate contains greater than about 50% solid phase matter. 
     
     
         12 . A system according to  claim 8  wherein, after dilution, the heat exchange medium contains from about 18% to about 50% solid phase matter. 
     
     
         13 . A system according to  claim 8  wherein the apparatus for diluting comprises a pump or pressurization device that is connectable to a vessel containing fresh liquid diluent. 
     
     
         14 . A system according to  claim 13  wherein the pump or pressurization device is connected to a vessel that contains a liquid diluent that has not previously circulated through the catheter. 
     
     
         15 . A system according to  claim 14  wherein the liquid diluent comprises a sterile solution suitable for intravenous administration. 
     
     
         16 . A system according to  claim 14  wherein the liquid diluent is selected from the group consisting of:
 saline solutions; 
 aqueous 0.9% NaCl solution; 
 water. 
 
     
     
         17 . A system according to  claim 8  wherein the apparatus for diluting comprises a conduit that delivers re-circulated heat exchange medium which has previously circulated through the catheter, wherein at least some of the solid phase matter has melted. 
     
     
         18 . A system according to  claim 17  further comprising a temperature sensor for sensing the temperature of the re-circulated heat exchange medium. 
     
     
         19 . A system according to  claim 17  further comprising an extracorporeal heat exchanger which alters the temperature of the re-circulated heat exchange medium. 
     
     
         20 . A system according to  claim 19  wherein the extracorporeal heat exchanger alters the temperature of the re-circulated heat exchange medium before it becomes combined with the heat exchange medium concentrate. 
     
     
         21 - 57 . (canceled)