Thermoregulation

Malignant hyperthermia is a syndrome of skeletal muscle hypermetabolism. It is a genetic susceptibility, triggered by succinylcholine and volatile anesthetics. In the most extreme cases, hypermetabolism can produce an arterial carbon dioxide concentration exceeding 150 mmHg, an arterial pH less than 6.8, and a core temperature of 43°C in as little as 30 minutes. Fortunately, most cases are considerably less impressive. Mortality associated with this syndrome was initially quite high, largely because temperature monitoring was not routine and end-tidal carbon dioxide monitoring was unavailable. Consequently, only the most severe cases were recognized. More importantly, however, no specific treatment was available. This changed with the introduction of intravenous dantrolene. Better monitoring, increased awareness, and effective treatment have combined to reduce mortality from malignant hyperthermia to a few percent. Major advances in our understanding of the malignant hyperthemiia syndrome include the following: