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Monday, May 20, 2013
Anesthetic agents and heat regeneration
Does diprivan, halothane or succinylcholine inhibit the body`s ability to regenerate heat?
Your body temperature is normally tightly controlled around a set point near 37 degrees centrigrade. Anesthetic agents (e.g. halothane, Diprivan) affect body temperature in one of two ways. First, they affect the body's thermostat, which is in the hypothalamus, a part of the brain. The effect of anesthetics is to widen the range of temperature that the hypothalamus allows. Second, anesthetics cause vasodilatation (widening of blood vessels) which causes heat to be redistributed from the "core" to the surface. Vasodilation causes a net heat loss from the body, and a decrease in core body temperature. The hypothalamus allows this drop in temperature.
Succinylcholine is a muscle relaxant that does not affect heat balance. However all muscle relaxants inhibit shivering, which is one of the compensatory mechanisms that your body uses when it becomes cold. Shivering generates heat through muscle contraction.
Various warming measures are used before, during and after anesthesia to try to maintain body temperature at or above 36 degrees centigrade. These include keeping the operating room as warm as tolerable, forced air warming blankets, warmed intravenous fluids, and so on.
Gareth S Kantor, MD
Assistant Professor of Anesthesiology
School of Medicine
Case Western Reserve University