[Malignant hyperthermia; two cases of MH in the presence of general anesthesia and performing caffeine contracture test].

In the present report we described two cases of malignant hyperthermia under halothane anesthesia. Case 1; A 54-year-old, 58 kg-male was scheduled for the operation of giant arterio-venous malformation. Anesthesia was induced with thiamylal, fentanyl and pancuronium, and maintained with oxygen, nitrous oxide and halothane. The patient was subjected to halothane inhalation for 26 hours prior to the development of the malignant hyperthermia. Although body temperature rose to 41 degrees C, it returned to normal with the administration of 280 mg of dantrolene and systemic cooling. Case 2; A 31-year-old, 68 kg-female was scheduled for tonsillectomy. Anesthesia was induced with thiamylal, oxygen, nitrous oxide and halothane. After the administration of 70 mg of SCC, marked muscular rigidity occurred and endotracheal intubation was impossible. The operation was postponed. Two months after the first anesthesia, operation was successfully performed under NLA with droperidol and fentanyl. Caffeine contracture test was performed in each case by skinned fiber method and the result showed that the sensitivity to caffeine increased in the isolated skeletal muscle fiber bundles from these patients. Thresholds of caffeine contracture of these skinned fiber bundles were all lower than 5mM caffeine.