Medical procedure
View Patent ↗The use of an intravascular cooling element to induce hypothermia in connection with a medical procedure. According to a first aspect of the present, invention, a coronary bypass procedure is conducted in which a patient's blood is oxygenated with the patient's lungs and in which blood is circulated using the patient's heart or using an intracorporeal pump. The procedure preferably comprises: (a) positioning a heat transfer element in a blood vessel of a patient; (b) cooling the body of the patient to less than 35° C., more preferably 32±2° C., using the heat transfer element; and (c) forming a fluid communicating graft between an arterial blood supply and the coronary artery. The body of the patient is preferably heated to about 37° C. using the heat transfer element subsequent to the step of forming the fluid communicating graft. According to a further aspect of the invention, a hypothermic medical procedure is provided while a patient is in a conscious or semiconscious state, comprising (a) administering a beta-blocking drug to the patient; (b) delivering a heat transfer element to a blood vessel of the patient; and (c) cooling a region of the patient or the body of the patient to less than 35° C. using the heat transfer element.
1. A coronary bypass procedure comprising:
positioning a heat transfer element in a blood vessel of a patient, wherein the heat transfer element comprises:
an inlet lumen to introduce a circulating working fluid; and
an outlet lumen to extract a circulating working fluid, the outlet lumen having a helical shape to induce turbulence in blood flowing past the outlet lumen and in the working fluid;
cooling the body of the patient to less than 35° C. using said heat transfer element; and
forming a fluid communicating graft between an arterial blood supply and the coronary artery;
wherein the patient's blood is oxygenated with the patient's lungs and wherein blood is circulated using the patient's heart or using an intracorporeal pump.
2. The coronary bypass procedure of claim 1 , wherein the heat transfer element absorbs at least 150 Watts of heat during cooling.
3. The coronary bypass procedure of claim 1 , further comprising warming the body of the patient to about 37° C. using said heat transfer element, subsequent to the step of forming the fluid communicating graft.
4. The coronary bypass procedure of claim 1 , wherein the step of forming a fluid communicating graft between the arterial blood supply and the coronary artery is preformed on a beating heart during bradycardia of the heart.
5. The coronary bypass procedure of claim 1 , wherein the heart is arrested or nearly arrested during at least a portion of the step of forming the fluid communicating graft.
6. The coronary bypass procedure of claim 5 , wherein the heart is chemically arrested.
7. The coronary bypass procedure of claim 5 , wherein the heart is electrically arrested.
8. The coronary bypass procedure of claim 5 , wherein the patient's circulation is supported with a pump positioned in the patient's vasculature.
9. The coronary bypass procedure of claim 8 , wherein the pump is at least partially positioned in the left ventricle.
10. The coronary bypass procedure of claim 9 , wherein the pump is introduced through the femoral artery.
11. The coronary bypass procedure of claim 1 , wherein the heartbeat is intermittently arrested and stimulated; and wherein at least a portion of the step of forming the fluid communicating graft is carried out during periods of heartbeat arrest.
12. The coronary bypass procedure of claim 11 , wherein the heart is chemically arrested and wherein the heartbeat is electrically stimulated.
13. The coronary bypass procedure of claim 12 , wherein the heart is chemically arrested using one or more beta-blockers.
14. The coronary bypass procedure of claim 11 , wherein the heart is electrically arrested and electrically stimulated.
15. The coronary bypass procedure of claim 1 , wherein the heat transfer element is positioned in the venous vasculature.
16. The coronary bypass procedure of claim 15 , wherein the heat transfer element is positioned in the inferior vena cava.
17. The coronary bypass procedure of claim 16 , wherein the heat transfer element is introduced into the femoral vein.
18. The coronary bypass procedure of claim 17 , wherein the heat transfer element is about 4 to 5 mm in diameter.
19. The catheter system of claim 1 , wherein the inlet lumen and the outlet lumen are made of a flexible material.
20. The catheter system of claim 19 , wherein the flexible material is rubber.
21. The catheter system of claim 19 , wherein the flexible material is a material capable of undergoing inflation.
22. The catheter system of claim 1 , further comprising more than one outlet lumen, each outlet lumen having a helical shape.
23. The catheter system of claim 1 , wherein the working fluid is saline.
24. The catheter system of claim 1 , wherein the helical shape of the outlet lumen is tapered when inflated.
25. The catheter system of claim 24 , wherein the helical shape of the outlet lumen is segmentally tapered when inflated.
26. The catheter system of claim 1 , wherein a radius of the inlet lumen decreases such that the inlet lumen is tapered when inflated.
27. The catheter system of claim 1 , wherein a radius of the outlet lumen decreases such that the outlet lumen is tapered when inflated.
28. The catheter system of claim 1 , wherein the helical shape of the outlet lumen is structured and shaped to have a geometry so as to induce turbulence within a free stream of blood flow when disposed in a blood vessel.
29. The catheter system of claim 1 , wherein the inlet lumen is substantially straight.
30. The catheter system of claim 1 , wherein the outlet lumen helically encircles the inlet lumen.
31. The coronary bypass procedure of claim 1 , wherein the use of a cardiopulmonary bypass system and obstruction of the ascending aorta are avoided.
32. The coronary bypass procedure of claim 1 , wherein the body of the patient is cooled to 32±2° C. using said heat transfer element.
33. The coronary bypass procedure of claim 6 , wherein the heart is arrested using a beta-blocker.