A new efficient method of topical cooling and rewarming of the myocardium.

Profound myocardial hypothermia (below 17 degrees C, and more often around 12 degrees C) is imperative in myocardial protection while the aorta is cross-clamped. Based on our experience in more than 800 open-heart operations, profound myocardial hypothermia can be achieved by very efficient topical cooling despite mild systemic hypothermia (30 to 33 degrees C) and a small, single dose of crystaloid K + cardioplegia. Very efficient topical cooling is achieved by a high flow (1 to 1(1/2) L/min) of continuously cooled fluid (+ 0.5 to + 2 degrees C). The great temperature-reducing capacity of the cooling system is due to a 10 to 15 meter long metal coil tube that is immersed in an ice-salt cold bath. The water pump placed in the bath makes heat exchange even more efficient. The described method of myocardial protection with stable profound myocardial hypothermia safely prolongs the ischemic time during operation to more than 2 hours. By repositioning the coil into the warm bath (39 to 40 degrees C), the whole system can be used for topical rewarming of the heart.