Malignant hyperthermia in the otolaryngologic patient: prospective anesthetic and surgical management of eight children.

Malignant hyperthermia (MH) is a rare genetic myopathy whose hallmark is rise in body temperature. This hypermetabolic state is triggered by inhalational anesthetics and/or depolarizing muscle relaxants such as succinylcholine. Even the use of dantrolene may not be protective against the hypermetabolic crisis. Eight patients at risk for MH undergoing tonsillectomy, adenoidectomy, and/or myringotomy with ventilation tube insertion were anesthetized with nitrous oxide, barbiturates, opiates, tranquilizers, and nondepolarizing muscle relaxants without dantrolene and without complication. Cardiac monitoring and rectal temperatures were followed. In order to provide additional evidence, all eight patients had vastus lateralis muscle biopsies with subsequent caffeine-halothane contracture studies performed. The contracture study showed positive results in seven of eight patients studied, indicating MH-susceptible muscle. No anesthetic or operative complications were encountered. This study demonstrates that patients at risk of developing MH crisis can have otolaryngologic procedures performed relatively safely while undergoing appropriately selected anesthesia.