[A case report of a 63-year-old patient with malignant hyperthermia]

We have experienced a case of fulminant malignant hyperthermia who was a 63-year-old female weighing 44 kg. There was no particular past history nor family history. She underwent right mastoidectomy because of chronic otitis media. Her preoperative physical status was ASA I. She was premedicated with diazepam 10 mg and loxatigine 75 mg P.O. The induction was done with thiamylal 200 mg IV and fentanyl 0.1 mg IV followed by vecuronium 6 mg IV for endotracheal intubation. Intubation was easy and uneventful. Anesthesia was maintained with nitrous oxide 3 l.min-1, oxygen 3 l.min-1 and enflurane 2.0%. Seventy min after the induction of anesthesia, arterial blood gas analysis showed severe respiratory acidosis (PCO2: 63.2 mmHg, pH: 7.27) and it was improved with manual hyperventilation at that time. Pulse rate increased from 80 to 115 b.p.m. 20 minutes later. Then, the patient was ventilated with 100% oxygen, and anesthetic circuits and machine were exchanged for new units. Surgery was postponed. Muscle stiffness of upper extremities was observed and her temperature increased to a maximum of 38.9 degrees C. Surface cooling was started and dantrolene sodium 60 mg and furosemide 20 mg were given intravenously. The patient was transferred to the intensive care unit, and clinical signs improved gradually within one hour. Serum enzymes; CPK, LDH, GOT and GPT increased on the first postoperative day. On the 11 th postoperative day skeletal muscle biopsy was done under local anesthesia with 1% procaine and Ca-induced Ca-release rate test revealed positive for enflurane. This is the oldest patient of malignant hyperthermia reported in Japan.