Abstract
A 10-year-old girl with myasthenia gravis had had bilateral ptosis for 8 years. Since dysphagia appeared despite multiple anticholinergic treatments, a thymectomy was scheduled. Her serum anti-acetylcholine receptor(anti-AChR)-antibody level was 0.7 nmol•l-1. The compound action potential of the abductor digiti minimi was monitored after train-of-four (TOF) stimulation of the ulnar nerve at the wrist. The initial TOFR value was 75 %. Fifteen minutes after inhalation of 2 MAC isoflurane, the T1 values decreased to 65%. Tracheal intubation was performed without the use of a muscle relaxant. Anesthesia was maintained with 66% N2O in oxygen, 1.2% isoflurane, and fentanyl as needed. As soon as the inhalation of isoflurane was stopped, good spontaneous respiration appeared. Her clinical course was uncomplicated during the perioperative period. We successfully managed the patient by careful monitoring of the neuromuscular functions without the use of muscle relaxants.
