Refrigeration source for a cryoablation catheter

Abstract

An apparatus and method for automatic operation of a refrigeration system to provide refrigeration power to a catheter for tissue ablation or mapping. The primary refrigeration system can be open loop or closed loop, and a precool loop will typically be closed loop. Equipment and procedures are disclosed for bringing the system to the desired operational state, for controlling the operation by controlling refrigerant flow rate, for performing safety checks, and for achieving safe shutdown. The catheter-based system for performing a cryoablation procedure uses a precooler to lower the temperature of a fluid refrigerant to a sub-cool temperature (−40° C.) at a working pressure (400 psi). The sub-cooled fluid is then introduced into a supply line of the catheter. Upon outflow of the primary fluid from the supply line, and into a tip section of the catheter, the fluid refrigerant boils at an outflow pressure of approximately one atmosphere, at a temperature of about −88° C. In operation, the working pressure is computer controlled to obtain an appropriate outflow pressure for the coldest possible temperature in the tip section.

1 - 39 . (canceled) 
     
     
         40 . A medical cooling system comprising:
 a medical device;   a console connectable to the medical device at a connection point, the console controlling the temperature of the medical device, and the console including a first system directing coolant in a mixed gas and liquid state to the medical device along a coolant supply line; and   a second system decreasing the percentage of gas in the coolant before the coolant reaches the connection point by controlling a temperature of the coolant.   
     
     
         41 . A medical cooling system comprising:
 a medical device;   a console connectable to the medical device at a connection point, the console controlling the temperature of the medical device, and the console including a first system directing coolant in a first state to the medical device along a coolant supply line; and   a second system decreasing the percentage of gas in the coolant before the coolant reaches the connection point by reducing a temperature of the coolant.   
     
     
         42 . A medical cooling system comprising:
 a medical device;   a console connectable to the medical device at a connection point, the console controlling the temperature of the medical device, and the console including a first system directing coolant in a first state to the medical device along a coolant supply line; and   a second system decreasing the percentage of gas in the coolant before the coolant reaches the connection point by controlling a temperature of the coolant;   wherein the second system decreases the percentage of gas in the coolant by reducing the temperature of the coolant, and wherein the system further comprises a chamber having an inlet and an outlet, wherein the chamber defines a fluid path from the inlet to the outlet, and the chamber envelops a portion of the coolant supply line; and   a controller for controlling coolant flow into the chamber.   
     
     
         43 . A medical cooling system comprising:
 a medical device;   a console connectable to the medical device at a connection point, the console controlling the temperature of the medical device, and the console including a first system directing coolant in a mixed gas and liquid state to the medical device along a coolant supply line; and   a second system decreasing the percentage of gas in the coolant before the coolant reaches the connection point by reducing a temperature of the coolant;   wherein the second system further comprises a chamber having an inlet and an outlet, wherein the chamber defines a fluid path from the inlet to the outlet, and the chamber envelops a portion of the coolant supply line; and   a controller for controlling coolant flow into the chamber.   
     
     
         44 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller, the controller being connected to the medical device at a connection point on the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through the connection point;   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point;   and wherein the second cooling system is disposed in a system component external to the coolant supply unit.   
     
     
         45 . The medical cooling system of  claim 44 , wherein the second cooling system includes an enclosure having a fluid inlet and a fluid outlet, the enclosure defining a fluid path from the inlet to the outlet, and the enclosure envelops the portion of the coolant supply line. 
     
     
         46 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller connected to the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point between the first cooling system and the medical device;   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point; and   wherein the second cooling system is disposed in a system component external to the coolant supply unit.   
     
     
         47 . The medical cooling system of  claim 46 , wherein the second cooling system includes an enclosure having a fluid inlet and a fluid outlet, the enclosure defining a fluid path from the inlet to the outlet, and the enclosure envelops the portion of the coolant supply line. 
     
     
         48 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller, the controller being connected to the medical device at a connection point on the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through the connection point; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point, wherein the second cooling system includes a heat exchanger, and wherein the second cooling system is disposed in a system component external to the coolant supply unit.   
     
     
         49 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller connected to the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point between the medical device and the first cooling system; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point, wherein the second cooling system includes a heat exchanger, and wherein the second cooling system is disposed in a system component external to the coolant supply unit.   
     
     
         50 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller, the controller being connected to the medical device at a connection point on the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point, wherein the second cooling system is disposed in a system component external to the coolant supply unit, and wherein the system component is a connection box disposed along the coolant supply line upstream of the connection point.   
     
     
         51 . The medical cooling system of  claim 50 , wherein the second cooling system includes a heat exchanger. 
     
     
         52 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller connected to the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point between the medical device and the first cooling system; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point, wherein the second cooling system is disposed in a system component external to the coolant supply unit, and wherein the system component is a connection box disposed along the coolant supply line upstream of the connection point.   
     
     
         53 . The medical cooling system of  claim 52 , wherein the second cooling system includes a heat exchanger. 
     
     
         54 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller, the controller being connected to the medical device at a connection point on the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point; wherein the second cooling system is disposed in a system component external to the coolant supply unit, and wherein the system component is connected to an external surface of the coolant supply unit.   
     
     
         55 . The medical cooling system of  claim 54 , wherein the second cooling system includes a heat exchanger. 
     
     
         56 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller connected to the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point between the medical device and the first cooling system; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point; wherein the second cooling system is disposed in a system component external to the coolant supply unit, and wherein the system component is connected to an external surface of the coolant supply unit.   
     
     
         57 . The medical cooling system of  claim 56 , wherein the second cooling system includes a heat exchanger. 
     
     
         58 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller, the controller being connected to the medical device at a connection point on the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point; wherein the second cooling system is disposed in a system component external to the coolant supply unit, and wherein the system component is disposed proximate to an external surface of the coolant supply unit.   
     
     
         59 . The medical cooling system of  claim 58 , wherein the second cooling system includes a heat exchanger. 
     
     
         60 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller connected to the proximal end of the medical device;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point between the medical device and the first cooling system; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point; wherein the second cooling system is disposed in a system component external to the coolant supply unit, and wherein the system component is disposed proximate to an external surface of the coolant supply unit.   
     
     
         61 . The medical cooling system of  claim 60 , wherein the second cooling system includes a heat exchanger. 
     
     
         62 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller, the controller being connected to the medical device at a connection point on the proximal end of the medical device, wherein the controller is disposed in the coolant supply unit;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through the connection point;   and a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point; wherein the second cooling system is disposed in a system component external to the coolant supply unit.   
     
     
         63 . A medical cooling system comprising:
 a coolant supply unit, and a medical device having distal and proximal ends;   a controller connected to the proximal end of the medical device, wherein the controller is disposed in the coolant supply unit;   a first cooling system directing coolant from the coolant supply unit to the medical device along a coolant supply line through a connection point between the medical device and the first cooling system; and   a second cooling system chilling the coolant within a portion of the coolant supply line upstream of the connection point; wherein the second cooling system is disposed in a system component external to the coolant supply unit.   
     
     
         64 . A medical cooling system, comprising:
 a medical device having distal and proximal end portions;   a console including a housing, a coolant supply in fluid communication with the medical device, wherein the coolant supply includes a controller,   one or more connecting lines coupling the console with the medical device, the one or more connecting lines including a coolant supply line; and   a system component disposed at an intermediate point between the proximal end portion of the medical device and the console, the system component including a subcooler disposed in thermal communication with a portion of the coolant supply line.   
     
     
         65 . The medical cooling system of  claim 64 , wherein the subcooler includes a heat exchanger. 
     
     
         66 . The medical cooling system of  claim 64 , wherein the system component is a connection box disposed around the coolant supply line. 
     
     
         67 . The medical cooling system of  claim 64 , wherein the system component is connected to an external surface of the housing of the console. 
     
     
         68 . A medical cooling system, comprising:
 a coolant supply;   a medical device having proximal and distal end portions, and having a coolant inlet line from the proximal end portion to the distal end portion, and a coolant return line from the distal end portion to the proximal end portion;   a coolant supply line between the coolant supply and the coolant inlet line;   a coolant recovery line between a source of vacuum and the coolant return line, the coolant supply line, coolant inlet line, coolant return line, and the coolant recovery line defining a first flow pathway from the coolant supply to the source of vacuum; and   a coolant exit line.   
     
     
         69 . The medical cooling system of  claim 68 , further comprising:
 a scavenging tank coupled to the source of vacuum, the medical cooling system being substantially open-loop.   
     
     
         70 . A medical cooling system, comprising:
 a coolant supply;   a medical device having proximal and distal end portions, and having a coolant inlet line from the proximal end portion to the distal end portion, and a coolant return line from the distal end portion to the proximal end portion;   a coolant supply line between the coolant supply and the coolant inlet line;   a coolant recovery line between a pump and the coolant return line, the coolant supply line, coolant inlet line, coolant return line, and the coolant recovery line defining a first flow pathway from the coolant supply to the pump; and   a coolant exit line.   
     
     
         71 . The medical cooling system of  claim 70 , further comprising:
 a scavenging tank coupled to the pump, the medical cooling system being substantially open-loop.   
     
     
         72 . A medical cooling system, comprising:
 a coolant supply;   a medical device having proximal and distal end portions, and having a coolant inlet line from the proximal end portion to the distal end portion, and a coolant return line from the distal end portion to the proximal end portion;   a coolant supply line between the coolant supply and the coolant inlet line;   a coolant recovery line between a source of vacuum and the coolant return line, the coolant supply line, coolant inlet line, coolant return line, and the coolant recovery line defining a first flow pathway from the coolant supply to the source of vacuum, wherein a portion of the first flow pathway includes a pressure indicator.   
     
     
         73 . A medical cooling system, comprising:
 a coolant supply;   a medical device having proximal and distal end portions, and having a coolant inlet line from the proximal end portion to the distal end portion, and a coolant return line from the distal end portion to the proximal end portion;   a coolant supply line between the coolant supply and the coolant inlet line;   a coolant recovery line between a pump and the coolant return line, the coolant supply line, coolant inlet line, coolant return line, and the coolant recovery line defining a first flow pathway from the coolant supply to the pump, wherein a portion of the first flow pathway includes a pressure indicator.   
     
     
         74 . A medical cooling system, comprising:
 a coolant supply;   a medical device having proximal and distal end portions, and having a coolant inlet line from the proximal end portion to the distal end portion, and a coolant return line from the distal end portion to the proximal end portion;   a coolant supply line between the coolant supply and the coolant inlet line;   a coolant recovery line between a source of vacuum and the coolant return line, the coolant supply line, coolant inlet line, coolant return line, and the coolant recovery line defining a first flow pathway from the coolant supply to the source of vacuum, wherein the first flow pathway includes a pressure indicator; and   a console coupled to the pressure indicator to control the flow of coolant in the first flow pathway.   
     
     
         75 . A medical cooling system, comprising:
 a coolant supply;   a medical device having proximal and distal end portions, and having a coolant inlet line from the proximal end portion to the distal end portion, and a coolant return line from the distal end portion to the proximal end portion;   a coolant supply line between the coolant supply and the coolant inlet line;   a coolant recovery line between a pump and the coolant return line, the coolant supply line, coolant inlet line, coolant return line, and the coolant recovery line defining a first flow pathway from the coolant supply to the pump, wherein the first flow pathway includes a pressure indicator; and   a console coupled to the pressure indicator to control the flow of coolant in the first flow pathway.   
     
     
         76 . A medical cooling system for affecting the temperature of a treatment site, comprising:
 a medical device;   a coolant supply;   a first coolant flow path between the medical device and the coolant supply;   a subcooler disposed about a portion of the first coolant flow path and having an inlet and an outlet;   a second coolant flow path between the coolant supply and the inlet; and   a controller coupled the subcooler, the controller controlling the flow of coolant through the first and second flow paths to regulate the temperature of the treatment site.