Method for endovascular management of body temperature
View Patent ↗The present invention provides a method and apparatus for controlling the internal body temperature of a patient. According to the present invention, a catheter is inserted through an incision into a large blood vessel of a patient. By selectively heating or cooling a portion of the catheter lying within the blood vessel, heat may be transferred to or from blood flowing within the vessel and the patient's body temperature may thereby be increased or decreased as desired. The invention will find use in treating undesirable conditions of hypothermia and hyperthermia, or for inducing a condition of artificial hypothermia when desired.
1. A method for altering the body temperature of a living patient having blood circulating through his or her vasculature, said method comprising the steps of:
A. providing a heat exchange catheter which is insertable into the lumen of a blood vessel of the patient, said heat exchange catheter having a distal end, a heat exchange region which occupies less than the entire length of the catheter body and has a heat exchange surface which comprises a helical protrusion, an inflow lumen through which a circulating heat exchange fluid flows into the heat exchange region an outflow lumen through which the circulating heat exchange fluid flows out of the heat exchange region;
B. inserting the heat exchange catheter, distal end first, into the patient's vasculature;
C. advancing the catheter to a position where the heat exchange region is is positioned within a blood vessel and the distal end of the catheter remains within the patient's vasculature;
D. circulating heat exchange fluid through the heat exchange region, causing heat to be exchanged, through the heat exchange surface, between the circulating heat exchange fluid and blood flowing through the blood vessel; and
E. adjusting the temperature of the circulating heat exchange fluid to cause the patient's body temperature to be maintained at or changed to a desired body temperature.
2. A method according to claim 1 wherein the patient's body temperature is lowered.
3. A method according to claim 1 wherein the patient's body temperature is lowered below 37 degrees C.
4. A method according to claim 1 wherein the patient's body temperature is raised.
5. A method according to claim 1 wherein the patient's body temperature is temporarily lowered to a hypothermic temperature.
6. A method according to claim 5 wherein the patient's body temperature is temporarily lowered to a temperature that is sufficiently low to reduce oxygen consumption of tissue within the patient's body.
7. A method according to claim 1 wherein the method is carried out to warm a patient who is hypothermic.
8. A method according to claim 1 wherein the method is carried out to cool a patient who is hyperthermic.
9. A method according to claim 1 wherein the external surface of the heat exchange region is maintained within a range between about 20 degrees C. and about 24 degrees C. when cooling.
10. A method according to claim 1 wherein the external surface of the heat exchange region is maintained below about 43 degrees C. when warming.
11. A method according to claim 1 further comprising the step of:
removing the catheter from the patient's vasculature.
12. A method according to claim 1 wherein the helical protrusion on the heat exchange surface serves to increase the heat exchange surface area.
13. A method according to claim 1 further comprising the steps of monitoring patient body temperature.
14. A method according to claim 13 wherein the heat exchange catheter further comprises a temperature sensor and wherein the step of monitoring patient body temperature is carried out using that temperature sensor.
15. A method according to claim 14 wherein the temperature sensor is located at the distal end of the catheter.