Effects of Atracurium in the Patients with Myasthenia Gravis Undergoing Thymectomy / 대한마취과학회지

ABSTRACT

BACKGROUND: Myasthenia gravis is an autoimmune neuromuscular disorder that shows increased sensitivity to nondepolarizing muscle relaxants. Atracurium is eliminated by Hofmann elimination and ester hydrolysis. We studied the onset and duration of atracurium in patients with myasthenia gravis. METHODS: Ten patients undergoing thymectomy for myasthenia gravis and ten patients of ASA Class I-II without liver, kidney and neuromuscular disease for orthopedic surgical procedures were assigned. Anesthesia was induced with thiopental (4~5 mg/kg) and maintained with inhalation of N2OO2 (11) and enflurane (1.0~2.0 vol%). Atracurium (0.5 mg/kg) was given as a muscle relaxant and then intubation was performed after twitch response was depressed more than 80%. Neuromuscular relaxation was assessed by TOF (T1) at the adductor pollicis with supramaximal stimulation of ulnar nerve at 2 Hz every 12 seconds. The onset and the duration of 5, 25, 50, 75% recovery time of T1 and the recovery index were recorded. RESULTS: Onset of block was shortened and recovery time of 5, 25, 50, 75% and recovery index were prolonged in patients with myasthenia gravis. Conlusions In patients with myasthenia gravis, atracurium induced rapid onset time and prolonged recovery time of 5, 25, 50, 75% and recovery index.