AAEM CASE-REPORT .29. PROLONGED PARALYSIS AFTER NEUROMUSCULAR BLOCKADE

Nondepolarizing neuromuscular blocking agents (NMBA) are being used wi th increasing frequency in critically ill patients. Recently, many cen ters have described patients with prolonged muscle weakness after long -term use of these agents, either alone or in combination with other a gents or disorders. Brief weakness lasting several hours to several da ys is probably the result of prolonged neuromuscular blockade, while m ore prolonged weakness lasting several weeks to months is, in all like lihood, caused by a myopathy. Patients with this myopathic disorder ha ve flaccid paralysis with intact cognition and sensation. Electrodiagn ostic findings include decreased M-wave amplitudes, positive waves and fibrillations, and rapid recruitment of small amplitude short duratio n, polyphasic motor unit potentials. Muscle biopsy findings include at rophy of type I and type II fibers, myofiber necrosis, and selective l oss of thick myofilaments. The myopathy is believed to be related to t he prolonged use of NMBA either alone or in combination with other dis orders or medications, particularly corticosteroids. The weakness expe rienced by these patients leads to additional respiratory compromise, difficulty weaning from the ventilator, and prolonged hospitalization. (C) 1995 Judith L. Gooch, MD. Published by John Wiley and Sons, Inc.