Control system for cryosurgery
AssigneeCryoGen, Inc.
InventorsRavikumar V. Kudaravalli, Hong Li
Life of this patent
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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.
Claims19
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.
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.
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.
Dependencies are inferred from the claim text.