Multi-lumen heat transfer catheter systems

1. Fluid circulation catheter apparatus comprising in combination: an elongated inlet fluid lumen having proximal and distal ends, said inlet lumen being defined by inlet lumen wall means and having fluid inlet means proximate to said proximal end wherein no portion of the inlet lumen or the inlet lumen wall means extends beyond the distal end of the inlet lumen; an elongated outlet fluid lumen having proximal and distal ends, said outlet lumen being defined by outlet lumen wall means and having fluid outlet means proximate to said proximal end; and a fluid connection whereby substantially all circulating fluid would pass directly from said inlet lumen to said outlet lumen at or proximate to the distal end of the inlet lumen.

2. Catheter apparatus according to claim 1 further comprising a fluid inside said inlet and outlet lumens, said fluid being maintained at a substantially constant temperature which is different from normal body temperature.

3. Catheter apparatus according to claim 1 further wherein said fluid connection means is located proximate to said distal ends of said inlet and outlet lumens.

4. Catheter apparatus according to claim 1 further comprising single-layer, integrally formed wall means comprising at least a portion of said inlet lumen wall means and at least a portion of said outlet lumen wall means, said integrally formed wall means separating the interior of said inlet lumen from the interior of said outlet lumen.

5. Catheter apparatus according to claim 4 wherein said fluid connection means comprises at least an aperture in said integrally formed wall means.

6. A catheter system to transfer thermal energy to or away from an internal body location and/or a body fluid by heat transfer to or from a working fluid, the system comprising:

an inlet lumen with proximal and distal ends; and,

an outlet lumen with proximal and distal ends, the outlet lumen coupled to the inlet lumen at a fluid connection location so as to transfer the working fluid between the two, the outlet lumen having a structure to induce turbulence in the body fluid or in the working fluid, and wherein the outlet lumen further comprises at least one shape or surface feature located proximal of the fluid connection location that induces turbulence in a working fluid passing through that lumen.

7. A method of changing the temperature of an internal body location and/or a body fluid, the method comprising the steps of:

providing an inflatable heat transfer element, the inflatable heat transfer element formed by at least an inlet lumen and an outlet lumen each having proximal and distal ends and a fluid connection between the distal ends at a fluid connection location, at least one of the inlet lumen or the outlet lumen having a turbulence-inducing shape located proximal of the fluid connection location;

inserting the inflatable heat transfer element into a vascular system;

delivering a circulating working fluid from a working fluid supply to the inflatable heat transfer element, the temperature of the circulating working fluid being different from that of the body fluid in the vascular system;

inflating the inflatable heat transfer element with the circulating working fluid;

inducing turbulence in the working fluid or in the body fluid by circulating the working fluid through the lumen having the turbulence-inducing shape, thereby enhancing heat transfer between the circulating working fluid and the body fluid; and,

returning the working fluid to the working fluid supply via the outlet lumen.

8. A method for treating a patient by providing heating or cooling at an internal body location and/or to a body fluid, the method comprising the steps of:

providing a catheter system comprising a catheter and a heating or cooling element attached to a distal end thereof, the heating or cooling element employing fluid mixing-inducing surface features;

inserting the catheter through the vascular system of the patient to place the heating or cooling element at a desired location along the vascular system;

circulating heat transfer fluid at a temperature different from that of the vascular system through the heating or cooling element whereby, at a fluid reversal location, fluid flowing in a distal direction instead flows in a proximal direction; and,

transferring heat between the heating or cooling element and the body fluid in the vascular system, whereby the body fluid is heated or cooled;

wherein the mixing-inducing surface features are located proximal of the fluid reversal location and are configured to cause mixing in the heat transfer fluid circulating through the heating or cooling element and/or in the body fluid in the vascular system having the heating or cooling element.

9. A method for cooling a patient's body intravascularly, the method comprising the steps of:

providing a catheter system comprising a catheter and a heating or cooling element attached to a distal end thereof, the heating or cooling element having a mixing-inducing shape and/or surface feature;

inserting the catheter through the vascular system of the patient to place the heating or cooling element at a desired location inside the patient;

circulating heat transfer fluid at a temperature different from that of the vascular system through the heating or cooling element including at least the element portion having the mixing-inducing shape and/or surface feature to create turbulence in the heat transfer fluid whereby, at a fluid reversal location, fluid flowing in a distal direction instead flows in a proximal direction and also where the mixing-inducing shape and/or surface feature to create turbulence is located proximal of the fluid reversal location; and,

transferring heat between the patient's vascular system and the heating or cooling element.

10. Catheter apparatus according to claim 1 further wherein no portion of the outlet lumen or the outlet lumen wall means extends beyond the distal end of the outlet lumen.