Comparison of the Effects of Etomidate and Propofol on Redistribution Hypothermia during General Anesthesia

Redistribution hypothermia is an internal core-to-peripheral redistribution of body heat during the first hour after the induction of general anesthesia. It is associated with several adverse clinical outcomes, including postoperative shivering, increased blood loss, 2) decreased drug metabolism and clearance, morbid myocardial outcomes, wound infection, and delayed recovery from anesthesia. Redistribution hypothermia results from anesthetic-induced central inhibition of tonic thermoregulatory vasoconstriction in the arteriovenous shunt and anesthetic-induced arterial and venous vasodilation. Once redistribution of body heat occurred, the heat which had escaped to the peripheral tissues could not be recovered by the core, as heat does not move up a temperature gradient. In the early period of anesthesia, alterations in core temperatures due to difference in systemic vascular resistance (SVR) of induction agents can affect the ultimate severity of redistribution hypothermia occurred during the first hour after the anesthetic induction. A major difference between etomidate and propofol has been observed in their impact on vasomotor tone. Etomidate results in a minimal degree of reduction in SVR, but propofol induces a severe drop in SVR. Accordingly, we tested the hypothesis that etomidate as an induction agent result in less redistribution hypothermia than propofol.