Acute quadriparesis in an asthmatic treated with atracurium

An 18-yr-old male asthmatic was paralyzed with atracurium for a period of seven days to facilitate mechanical pulmonary ventilation. After withdrawal of the muscle relaxant, train-of-four neuromuscular monitoring demonstrated rapid recovery of normal function. Three days later he developed acute quadriparesis without respiratory compromise. Electrophysiological studies showed normal conduction velocities, low compound muscle action potential amplitudes and evidence of denervation. Most cases of post-ventilatory weakness in the ICU involve the use of vecuronium and pancuronium. It has been suggested that the steroid nucleus in these muscle relaxants may be responsible. Our patient developed generalised weakness after treatment with atracurium, a benzylisoquinolinium muscle relaxant. Thus, it appears that the steroid nucleus of vecuronium and pancuronium is not essential in causing post-ventilatory weakness.