초록 ▼

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 dis

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.

대표청구항 ▼

We claim: 1. Apparatus for performing cryosurgery, comprising: a refrigerant supply source connectable to a high pressure duct; a cryosurgery catheter having an inlet connectable to said high pressure duct, said catheter having a tip; a refrigerant expansion element in said catheter; a temperatu

We claim: 1. Apparatus for performing cryosurgery, comprising: a refrigerant supply source connectable to a high pressure duct; a cryosurgery catheter having an inlet connectable to said high pressure duct, said catheter having a tip; a refrigerant expansion element in said catheter; a temperature sensor on said catheter; a pressure sensor adapted to sense pressure inside said catheter tip; a low pressure duct connectable to an outlet of said catheter; a flow sensor in said low pressure duct downstream of said catheter; and a control system connected and programmed to maintain a selected catheter temperature, in response to signals from said temperature sensor, said pressure sensor, and said flow sensor. 2. An apparatus as recited in claim 1, further comprising: a precool heat exchanger in said high pressure duct; a precool compressor for compressing a secondary refrigerant; and a precool expansion element connected to said precool compressor for expanding said secondary refrigerant to cool said precool heat exchanger. 3. An apparatus as recited in claim 2, further comprising a bypass valve connected between an outlet of said precool compressor and an inlet of said precool compressor. 4. An apparatus as recited in claim 1, wherein: said refrigerant supply source comprises a pressure bottle; and a fluid controller in said high pressure duct; and further comprising a recovery bottle connected to said low pressure duct. 5. An apparatus as recited in claim 4, wherein said fluid controller comprises a pressure controller. 6. An apparatus as recited in claim 4, wherein said fluid controller comprises a flow controller. 7. An apparatus as recited in claim 4, further comprising: a vacuum pump having an inlet connected to said low pressure duct; a recovery pump having an inlet connected to an outlet of said vacuum pump, said recovery pump having an outlet connected to said recovery bottle; a bypass valve in a bypass duct connected between said high pressure duct and said low pressure duct; and a vent valve connected to said bypass duct between said bypass valve and said high pressure duct. 8. An apparatus as recited in claim 1, wherein: said refrigerant supply source comprises a compressor; said high pressure duct is connected to an outlet of said compressor; a compressor controller; and said control system operates said compressor controller to maintain refrigerant pressure above a selected level in said high pressure duct. 9. An apparatus as recited in claim 8, further comprising a second compressor with a second compressor controller; wherein: said low pressure duct is connected to an inlet of said second compressor; an outlet of said second compressor is connected to an inlet of said first compressor; said control system operates said first compressor controller to maintain refrigerant pressure above a selected level in said high pressure duct; and said control system operates said second compressor controller to maintain refrigerant pressure below a selected level in said low pressure duct. 10. An apparatus as recited in claim 8, further comprising a bypass valve in a bypass duct connected between said high pressure duct and said low pressure duct. 11. An apparatus as recited in claim 1, further comprising: a precool heat exchanger in said high pressure duct; a precool compressor for compressing a secondary refrigerant; a precool expansion element connected to said precool compressor for expanding said secondary refrigerant to cool said precool heat exchanger; and a bypass valve connected between an outlet of said precool compressor and an inlet of said precool compressor wherein: said refrigerant supply source comprises a primary compressor; said high pressure duct is connected to an outlet of said primary compressor; and said control system operates said bypass valve to maintain catheter temperature at a selected level. 12. Apparatus for performing cryosurgery, comprising: a primary refrigerant pressure bottle connectable to a high pressure duct; a fluid pressure controller in said high pressure duct; a precool heat exchanger in said high pressure duct; a precool compressor for compressing a secondary refrigerant; a secondary expansion element connected to expand said secondary refrigerant to cool said precool heat exchanger; a cryosurgery catheter having an inlet connectable to said high pressure duct; a primary expansion element in said catheter connected to expand said primary refrigerant to cool a portion of said catheter; a temperature sensor on said catheter; a low pressure duct connectable to an outlet of said catheter; a pressure sensor in said low pressure duct; a flow sensor in said low pressure duct; a vacuum pump having an inlet connected to said low pressure duct; a recovery pump having an inlet connected to an outlet of said vacuum pump; a recovery bottle connected to an outlet of said recovery pump; a bypass valve in a bypass duct connected between said high pressure duct and said low pressure duct; and a control system connected and programmed to operate said pressure controller to maintain a selected primary refrigerant flow rate, in response to signals from said temperature sensor, said pressure sensor, and said flow sensor. 13. A method for controlling a cryosurgical instrument, comprising: providing a refrigerant supply, a cryosurgery catheter including an expansion element, a temperature sensor, a pressure sensor, a flow sensor, a precool loop, and a control system connected to said sensors; flowing said refrigerant via a high pressure duct into said cryosurgery catheter; precooling said refrigerant in said precool loop; expanding said refrigerant in said catheter with said expansion element; sensing the temperature of said catheter with said temperature sensor; sensing the pressure of said expanded refrigerant with said pressure sensor; sensing the flow rate of said refrigerant with said flow sensor; and controlling said refrigerant with said control system, to maintain a selected catheter temperature, in response to signals from said temperature sensor, said pressure sensor, and said flow sensor. 14. A method as recited in claim 13, wherein: said refrigerant supply source comprises a pressure bottle; and a fluid controller in said high pressure duct; said method comprising operating said fluid controller to maintain a selected pressure at said pressure sensor. 15. A method as recited in claim 14, wherein said fluid controller comprises a pressure controller, said method comprising modifying a pressure setpoint of said pressure controller to maintain a selected pressure at said pressure sensor. 16. A method as recited in claim 14, wherein said fluid controller comprises a flow controller, said method comprising modifying a flow setpoint of said flow controller to maintain a selected pressure at said pressure sensor. 17. A method as recited in claim 13, wherein: said refrigerant supply source comprises a compressor; and a compressor controller; said method comprising operating said compressor controller to maintain a selected pressure at said pressure sensor. 18. A method as recited in claim 17, further comprising: providing a second compressor with a second compressor controller, wherein a low pressure duct is connected between said catheter and an inlet of said second compressor, and an outlet of said second compressor is connected to an inlet of said first compressor; operating said control system and said first controller to maintain refrigerant pressure above a selected level in said high pressure duct; and operating said control system and said second controller to maintain refrigerant pressure below a selected level in said low pressure duct. 19. A method as recited in claim 13, wherein: said refrigerant supply source comprises a compressor; and a precool bypass valve in said precool loop; said method comprising operating said precool bypass valve to maintain a selected catheter temperature.