System and method for controlling rate of heat exchange with patient

• US 20040127851A1
• Filed: 12/31/2002
• Published: 07/01/2004
• Est. Priority Date: 12/31/2002
• Status: Active Grant

• Current Assignee: Zoll Circulation Incorporated (Asahi Kasei Corporation)
• Original Assignee: Alsius Corporation
• Inventors: Balding, David P., Whitebook, Mark Evan, Evans, Scott M., Noda, Wayne A.
• Granted Patent: US 7,278,984 B2
• Time in Patent Office: Days
• US Class Current: 604/113
• CPC Class Codes: A61F 2007/0054 with a closed fluid circuit, e.g. hot water
• CPC Class Codes: A61F 2007/126 for invasive application, e.g. for introducing into blood vessels
• CPC Class Codes: A61F 7/0085 Devices for generating hot or cold treatment fluids
• CPC Class Codes: A61F 7/12 Devices for heating or cooling internal body cavities

Abstract

A patient control system uses a patient-implanted catheter in thermal communication with a fluid bath via a circulating fluid circuit. A controller automatically controls the temperature of the fluid bath as required for selectively cooling or heating the patient in accordance with patient temperature measurements. The controller thermally decouples the catheter and patient from the fluid bath during changes in fluid bath temperatures in order to overcome the effects of system thermal mass.

Claims

1. A method for changing the temperature of the body of a patient using a thermal exchange device, comprising:

transferring heat between the body of the patient and the thermal exchange device at a first heat transfer rate;

thermally decoupling the thermal exchange device from the body of the patient; and

transferring heat between the body of the patient and the thermal exchange device at a second heat transfer rate.

2. The method of claim 1, wherein transferring heat comprises:

implanting a catheter into the body of the patient; and

circulating a heat exchange fluid in heat exchange relationship with the catheter and the thermal exchange device.

3. The method of claim 2, wherein thermally decoupling the thermal exchange device from the body of the patient comprises reducing the circulation rate of the heat exchange fluid to a vanishingly low level.

4. The method of claim 3, further comprising:

determining the temperature of the patient relative to a predetermined target temperature or range; and

determining the temperature of the thermal exchange device,

wherein thermally decoupling is performed when the temperature of the body of the patient is greater than the predetermined target temperature or range but is less than the temperature of the thermal exchange device, or when the temperature of the body of the patient is less than the predetermined target temperature or range but is greater than the temperature of the thermal exchange device.

5. The method of claim 3, further comprising:

determining the temperature of the patient relative to a predetermined target temperature or range;

determining the temperature of the thermal exchange device; and

thermally coupling the thermal exchange device and the body of the patient when the temperature of the body of the patient is less than the predetermined target temperature or range and is less than the temperature of the thermal exchange device, or when the temperature of the body of the patient is greater than the predetermined target temperature or range and is greater than the temperature of the thermal exchange device.

6. The method of claim 1, wherein the first heat transfer rate is one of cooling or heating the body of the patient, and the second heat transfer rate is the other of cooling or heating the body of the patient.

7. The method of claim 1, wherein both the first and second heat transfer rates comprise cooling the body of the patient, or both comprise heating the body of the patient.

8. A method for changing the temperature of the body of a patient using a catheter in heat exchange relationship with a fluid bath, the method comprising:

establishing a first fluid bath temperature;

when the fluid bath is at the first fluid bath temperature, transferring heat between the fluid bath and the body of the patient;

thermally decoupling the fluid bath from the body of the patient;

establishing a second fluid bath temperature; and

when the fluid bath is at the second fluid bath temperature, transferring heat between the fluid bath and the body of the patient.

9. The method of claim 8, wherein thermally decoupling is performed when the temperature of the body of the patient is greater than a predetermined target temperature or range but is less than the temperature of the fluid bath, or when the temperature of the body of the patient is less than the predetermined target temperature or range but is greater than the temperature of the fluid bath.

10. The method of claim 8, wherein the heat exchange relationship between the patient and the fluid bath is established using a circulating heat exchange fluid, and wherein thermally decoupling the fluid bath from the body of the patient comprises reducing the circulation rate of the heat exchange fluid to a vanishingly low level.

11. The method of claim 8, further comprising thermally coupling the fluid bath and the body of the patient when the temperature of the body of the patient is less than a predetermined target temperature or range and is less than the temperature of the fluid bath, or when the temperature of the body of the patient is greater than the predetermined target temperature or range and is greater than the temperature of the fluid bath.

12. The method of claim 11, wherein the heat exchange relationship between the patient and the fluid bath is established using a heat exchange fluid, and wherein thermally coupling the fluid bath and the body of the patient comprises circulating the heat exchange fluid.

13. The method of claim 8, wherein the direction of heat transfer is the same at both the first and second fluid bath temperatures.

14. The method of claim 8, wherein the direction of heat transfer at the first fluid bath temperature is different from the direction of heat transfer at the second fluid bath temperature

15. A system for changing the temperature of a patient using a catheter implanted in the patient, the system comprising:

a fluid bath;

a fluid circuit adapted to contain a circulating heat exchange fluid in heat exchange relationship with the fluid bath and the catheter;

a pump operable to circulate the heat exchange fluid in the fluid circuit; and

a controller adapted to control the pump such that circulation of the heat exchange fluid in the fluid circuit is reduced to a vanishingly low level during a change in the temperature of the fluid bath between a first level and a second level when the catheter is implanted in the patient.

16. The system of claim 15, wherein the temperature of the fluid bath is greater than the temperature of the patient at both the first and second levels, or is lower than the temperature of the patient at both the first and second levels.

17. The system of claim 15, wherein the temperature of the fluid bath is greater than the temperature of the patient at one of the first and second levels, and is less than the temperature of the patient at the other of the first and second levels.

18. A system for changing the temperature of a patient using a catheter implanted in the patient, the system comprising:

a thermal exchange device;

a fluid circuit adapted to contain a circulating heat exchange fluid in heat exchange relationship with the thermal exchange device and the catheter; and

a controller adapted to thermally decouple the catheter from the thermal exchange device during a change in the temperature of the thermal exchange device between a first level and a second level when the catheter is implanted in the patient.

19. The system of claim 18, further comprising:

a first temperature sensor which provides body temperature signals to the controller indicative of the temperature of the patient;

a second temperature sensor which provides thermal exchange device temperature signals to the controller indicative of the temperature of the thermal exchange device,

wherein the controller thermally decouples the catheter from the thermal exchange device in response to the body temperature signals and the thermal exchange device temperature signals.

20. The system of claim 18, wherein thermally decoupling is performed when the temperature of the body of the patient is greater than a predetermined target temperature or range but is less than the temperature of the thermal exchange device, or when the temperature of the body of the patient is less than a predetermined target temperature or range but is greater than the temperature of the thermal exchange device.

21. The system of claim 18, wherein the controller thermally couples the catheter to the thermal exchange device when the temperature of the body of the patient is less than a predetermined target temperature or range and is less than the temperature of the thermal exchange device, or when the temperature of the body of the patient is greater than a predetermined target temperature or range and is greater than the temperature of the thermal exchange device.

22. The system of claim 18, wherein the temperature of the fluid bath is greater than the temperature of the patient at both the first and second levels, or is lower than the temperature of the patient at both the first and second levels.

23. The system of claim 18, wherein the temperature of the fluid bath is greater than the temperature of the patient at one of the first and second levels, and is less than the temperature of the patient at the other of the first and second levels.

24. The system of claim 18, wherein the thermal exchange device is a fluid bath.

25. The system of claim 20, further comprising an input device through which the predetermined temperature or range are provided by an operator.

26. The system of claim 21, further comprising an input device through which the predetermined temperature or range are provided by an operator.

27. A system for changing the temperature of a patient using a catheter implanted in the patient, the system comprising:

heating and/or cooling means;

means for transferring heat between the heating and/or cooling means and the catheter; and

means for thermally decoupling the catheter from the heating and/or cooling means during a change in the temperature of the heating and/or cooling means between a first level and a second level when the catheter is implanted in the patient.

28. A method for driving the temperature of the body of a patient to a predetermined target temperature or range using a thermal exchange device, comprising:

thermally coupling the thermal exchange device and the body of the patient when the temperature of the body of the patient is less than the predetermined target temperature or range and is less than the temperature of the thermal exchange device, or when the temperature of the body of the patient is greater than the predetermined target temperature or range and is greater than the temperature of the thermal exchange device; and

thermally decoupling the thermal exchange device and the body of the patient when the temperature of the body of the patient is greater than the predetermined target temperature or range but is less than the temperature of the thermal exchange device, or when the temperature of the body of the patient is less than the predetermined target temperature or range but is greater than the temperature of the thermal exchange device.

29. The method of claim 28, wherein thermally coupling comprises circulating a heat exchange fluid between the thermal exchange device and a catheter implanted in the body of the patient, and wherein thermally decoupling comprises causing cessation of circulation of said fluid.