Heat production during anesthetic-induced malignant hyperthermia.

Malignant hyperthermia (MH) is a pharmacogenetic disease which predisposes to the trigger of a life-threatening, hypermetabolic syndrome by potent inhaled anesthetics and by depolarizing skeletal muscle relaxants. Heat production in the anesthetized MH can be profound with 5-fold increases in oxygen consumption. The trigger anesthetics cause an abnormal, sustained rise in myoplasmic calcium levels. Possible mechanisms by which continuous release of calcium from skeletal muscle sarcoplasmic reticulum stores can produce the profound hyperthermia are discussed. Mutations in the gene coding the ryanodine receptor calcium release channel have been found in MH families and these mutant channels may be the functional basis for MH.