System and method employing indwelling RF catheter for systemic patient warming by application of dielectric heating

• US 6,529,775 B2
• Filed: 01/16/2001
• Issued: 03/04/2003
• Est. Priority Date: 01/16/2001
• Status: Expired due to Term

• Current Assignee: Zoll Circulation Incorporated (Asahi Kasei Corporation), QUASIMOTO
• Original Assignee: Alsius Corporation
• Inventors: Whitebook, Mark Evan, Walker, Blair D., Shimada, Lynn M., Evans, Scott M.
• Primary Examiner(s): GIBSON, ROY DEAN
• Application Number:
  US09/761,069
• Publication Number:
  US 20020095198A1
• Time in Patent Office: 777 Days
• Field of Search: 607/96-102, 607/104-106, 607/113, 606/27-29, 606/31
• US Class Current: 607/101
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61F 2007/126 for invasive application, e.g. for introducing into blood vessels
• CPC Class Codes: A61F 7/12 Devices for heating or cooling internal body cavities
• CPC Class Codes: A61M 25/0017 specially adapted for long-term hygiene care, e.g. urethral or indwelling catheters to prevent infections

Abstract

An indwelling RF catheter achieves warming of patients by dielectric heating of blood or other bodily fluids. In one example, the catheter is deployed in a suitable blood vessel, such as the inferior vena cava. The catheter design includes an emitter structure electrically coupled to an RF generator, which provides a source of RF power. The emitter structure, distally located upon the catheter, administers electromagnetic radiation to the blood within the patient, thereby creating heat due to the dielectric qualities of blood. As blood heated by the indwelling RF catheter courses through the patient'"'"'s body, the patient'"'"'s body is systemically warmed, raising the body core temperature.

Claims

1. A patient warming method, comprising operation of:

providing a flow-through emitter wherein the emitter comprises an elongated inner electrode residing within and substantially coaxial to a hollow, elongated outer electrode;

utilizing a catheter to position the flow-through emitter within a body cavity of a patient;

the emitter structure allowing bodily fluids within the body cavity to flow through the emitter;

during the flow of bodily fluids through the emitter, operating the emitter to radiate electromagnetic energy sufficient to warm the fluids flowing through the emitters.

2. A patient warming method, comprising operations of:

providing a flow-through emitter structure comprising an elongated inner electrode residing within and substantially coaxial to a hollow, elongated outer electrode;

utilizing a catheter to position the flow-through emitter structure within a body cavity of a patient;

the emitter structure permitting bodily fluids to pass between the inner and outer electrodes;

during passage of bodily fluids through the emitter, operating the emitter to radiate electromagnetic energy sufficient to warm the bodily fluids.

3. A patient warming method, comprising operations of:

utilizing a catheter to position a multi-polar emitter structure within a blood-bearing body cavity of a patient, wherein the blood flows past the emitter,

during the flow of blood past the emitter, operating the emitter to create an electromagnetic field between the multiple poles sufficient to warm blood present in the cavity; and

continuing radiation of electromagnetic energy to achieve a selected increase in body core temperature of the patient through the warming of blood.

4. The method of claim 3, where the operation of utilizing a catheter to position a multi-polar emitter structure within a selected blood-bearing body cavity of a patient comprises:

positioning an elongated emitter structure comprising an elongated emitter body and multiple electrodes spiraling about the emitter body in substantially parallel paths.

5. A patient warming method, comprising operation of:

providing an emitter structure comprising an elongated emitter body and multiple electrodes spiraling about the emitter body in substantially parallel paths;

utilizing a catheter to position the emitter structure within a patient'"'"'s body cavity such that the emitter structure is immersed in bodily fluid;

creating an electromagnetic field between the electrodes sufficient to warm bodily fluid surrounding the emitter structure.

6. A patient warming method, comprising operations of:

providing an elongated emitter, including one or more electrodes and also including fluid permeable spacing structure situated about the emitter;

utilizing a catheter to position the emitter within a body cavity of a patient;

operating the electrodes to radiate electromagnetic energy sufficient to bodily fluids present in the cavity; and

while the emitter structure is positioned within the body cavity, the spacing structure resiliently separating the electrodes from walls of the body cavity while permitting bodily fluids to pass through the spacing structure.

7. The method of claim 6, where:

the operation of providing a spacing structure comprising providing resilient spacers attached to the emitter body;

the separating operation comprising the resilient spacers exerting pressure outward from the electrodes against walls of the body cavity.

8. The method of claim 6, where:

the operation of providing an emitter comprising providing an emitter body including resilient spacers attached to the emitter body, the spacers comprising wires each having a proximal end attached to the emitter body and a distal end projecting form the emitter body at an acute angle with respect to a longitudinal axis of the emitter body;

the operation of providing separation comprising the wires distancing the emitter body from walls of a body cavity while the emitter structure is positioned within the body cavity.

9. The method of claim 6, where:

the operation of providing an emitter comprising providing an emitter body including resilient spacers attached to the emitter body, the spacers comprising wires each having a proximal end attached to the emitter body and a distal end projecting from the emitter body at an acute angle with respect to a longitudinal axis of the emitter body, the emitter body and spacers being surrounded by a collapsible sheath;

the operation of providing separation comprising the wires distancing the emitter body from the sheath.

10. The method of claim 6, where:

the operation of providing an emitter comprising;

providing an elongated emitter body having a proximal end and also having an opposing, distal end, the emitter body including one or more electrodes operable to radiate electromagnetic energy;

provides multiple resilient spacers each coupled to a distal mount at the emitter body'"'"'s distal end and also coupled to a proximal mount longitudinally disposed from the distal end, where at least one of the distal mount and proximal mount are longitudinally movable along the emitter body;

provides remote actuator coupled to at least one of the distal and proximal mounts;

the separating operation comprising operating the remote actuator to move at least one of the distal and proximal mounts longitudinally along the emitter body in order to slacken the spacers to create bights therein.

11. A catheter apparatus, comprising:

an elongated catheter having a distal end;

an elongated emitter structure having a proximal end attached to the catheter and also an opposing, distal end, the emitter structure including one or more electrodes;

a blood temperature sensor;

a tether flexibly coupling the temperature sensor to the emitter structure'"'"'s distal end to suspend the sensor downstream of the emitter structure under influence of blood flow in the cavity.

12. A catheter apparatus, comprising:

an elongated catheter having a distal end;

an elongated emitter structure having a proximal end attached to the catheter and also an opposing, distal end, the emitter structure including one or more electrodes;

a blood temperature sensor;

means for coupling the temperature sensor to the emitter structure'"'"'s distal end to suspend the sensor downstream of the emitter structure under influence of blood flow in the cavity.

13. A catheter apparatus, comprising:

an elongated catheter having a distal end;

an elongated emitter structure having a proximal end attached to the catheter'"'"'s distal end and also an opposing, distal end, the emitter structure comprising;

a hollow elongated outer electrode;

an elongated inner electrode;

one or more spacers positioning the inner electrode within and substantially coaxial with the outer electrode to define a blood flow path between inner and outer electrodes.

14. A catheter apparatus, comprising:

an elongated catheter having a distal end;

an elongated emitter structure having a proximal end attached to the catheter'"'"'s distal end and also an opposing, distal end, the emitter structure comprising;

a hollow elongated outer electrode;

an elongated inner electrode;

means for positioning the inner electrode within an substantially coaxial with the outer electrode to define a blood flow path between inner and outer electrodes.

15. A patient warming method, comprising operations of:

utilizing a catheter to position an emitter within a blood-bearing body cavity of a patient, the emitter including a tether coupling a temperature sensor to a distal end of the emitter,

wherein the blood flows past the emitter, the tether suspending the temperature sensor downstream of the emitter in the body cavity under influence of blood flow in the cavity;

during the flow of blood past the emitter, operating the emitter to radiate electromagnetic energy sufficient to warm blood present in the cavity; and

operating the temperature sensor to sense temperature of blood within the body cavity.

16. A catheter apparatus, comprising:

an elongated catheter having a distal end;

an elongated emitter structure having a proximal end attached to the catheter and also an opposing, distal end, the emitter body including one or more electrodes operable to radiate electromagnetic energy;

a fluid permeable spacing structure attached to the emitter body to resiliently distance the emitter structure from walls of a body cavity while the emitter structure is positioned within the body cavity, wherein the spacing structure comprises multiple wires each having a proximal end attached to the emitter body and a distal end projecting from the emitter body at an acute angle with respect to a longitudinal axis of the emitter body.

17. The apparatus of claim 16, further comprising:

balls attached to the wires'"'"' distal ends.

18. The apparatus of claim 16, further comprising:

pads attached to the wires'"'"' distal ends.

19. The apparatus of claim 16, the wires forming a rounded loop at their distal ends.

20. The apparatus of claim 16, further comprising:

a collapsible sheath surrounding the emitter body and spacing structure.

21. A catheter apparatus, comprising:

an elongated catheter having a distal end;

an elongated emitter body having a proximal end attached to the catheter'"'"'s distal end and also having an opposing, distal end, the emitter body including one or more electrodes operable to radiate electromagnetic energy;

multiple resilient spacers each coupled to a distal mount at the emitter body'"'"'s distal end and also coupled to a proximal mount longitudinally disposed from the distal end;

at least one of the distal mount and proximal mount being longitudinally movable along the emitter body;

a remote actuator operable to move at least one of the distal and proximal mounts longitudinally along the emitter body to selectively slacken the spacers to create bights therein.

22. The apparatus of claim 21, the distal mount comprising a tip surrounding the emitter body'"'"'s distal end.

23. The apparatus of claim 21, the proximal mount comprising a ring surrounding the emitter body.

24. The apparatus of claim 21, the distal mount being fixed and the proximal mount being movable, the remote actuator comprising an activating line coupled to the proximal mount.

25. The apparatus of claim 21, the proximal mount being fixed and the distal mount being movable, the remote actuator comprising an activating line coupled to the distal mount.

26. The apparatus of claim 21, further comprising:

a resilient coupling between the distal mount and the emitter body urging the distal mount outward from the emitter body.

27. The apparatus of claim 21, further comprising:

a resilient coupling between the proximal mount and the emitter body urging the proximal mount proximally upon the emitter body.

28. A catheter apparatus, comprising:

an elongated catheter having a distal end;

an elongated emitter body having a proximal end attached to the catheter'"'"'s distal end and also having an opposing, distal end, the emitter body including one or more electrodes operable to radiate electromagnetic energy;

multiple resilient spacers each coupled to a distal mount at the emitter body'"'"'s distal end and also coupled to a proximal mount longitudinally disposed from the distal end;

at least one of the distal mount and proximal mount being longitudinally movable along the emitter body;

remotely actuated means for selectively slackening the spacers to create spacing bights therein by moving at least one of the distal and proximal mounts longitudinally along the emitter body.