PROSPECTIVE MANAGEMENT OF MALIGNANT HYPERTHERMIA IN THE GENERAL-SURGERY PATIENT

Malignant hyperthermia (MH) is a seemingly rare genetic myopathy. Hypermetabolic crisis accompanied by a rise in body temperature to as high as 44-degrees-C is its hallmark. MH is usually triggered by potent inhaled anesthetics and/or depolarizing muscle relaxants. Because of the extraordinary risk of death in patients who are susceptible, general surgeons may be reluctant to operate on these patients. Five such patients were referred to the General Surgery Service and the UCLA Malignant Hyperthermia Center following general surgical procedures aborted for first episodes of MH (4) or for strong family history of MH (1). They were anesthetized with nitrous oxide, barbiturates, opiates, tranquilizers and nondepolarizing muscle relaxants. The patients were not treated prophylactically with dantrolene. Cardiac monitoring, end-tidal pCO2 and rectal temperatures were followed. After completion of their general surgical procedures, 4 patients had a vastus lateralis muscle biopsy and 1 patient had an external oblique muscle biopsy, with subsequent caffeine/halothane contracture studies completed. The contracture study was positive in all 5 patients. No anesthetic or surgical complications were encountered. This study demonstrates that, using our protocol, patients at risk of developing MH crisis can have general surgical procedures performed safely while undergoing appropriately selected general anesthesia.