Cerebral hyperthermia and cardiac surgery: consequences and prevention.

Temperature management during cardiac surgery deserves considerable attention because it has broad effects, altering virtually every physiologic process, including oxygen demand, blood flow, cardiac output, and coagulation. Temperature is also important in cardiac surgery because virtually all patients undergo significant temperature change. These changes can be unique in mammalian physiology both with regard to their magnitude and rate of change. Furthermore, cardiac surgical patients may be uniquely vulnerable to the effects of temperature. Because of vascular disease and embolization, many patients are at risk for cerebral ischemia. Additionally, their cardiac, pulmonary, and renal reserve is typically limited; and there is risk for perioperative bleeding. Patient temperature can affect all of these processes and has its greatest effect on those who are physiologically most fragile. An appreciation for temperature management is also compelling because, unlike new technologies, procedures, or drugs; temperature management is simple, practical, applicable to every patient, and can be performed with very little cost. This article will show why cerebral hyperthermia should be avoided in cardiac surgery. Second, it will discuss why it occurs and the management steps that may prevent it. Finally, we will highlight recent discussion of postoperative hyperthermia and speculate as to its origin and relevance. Copyright 2001 by W.B. Saunders Company