Resistance to pancuronium in an asthmatic patient treated with aminophylline and steroids

A 17 year old male with a history of bronchial asthma was admitted to the intensive care unit in severe respiratory distress. During a two week period of intensive respiratory care he received large doses of aminophylline and corticosteroids. In addition, pancuronium was given to facilitate ventilation and to reduce airway pressure. Large doses of pancuronium, as much as 5 mg/hr, were required to stop spontaneous respiratory efforts and restlessness. The total pancuronium dose given during the two week period was 800 mg. One hour after pancuronium was discontinued the patient could open his eyes and move his lips. Peripheral nerve stimulation indicated partial paralysis which improved promptly following a test dose of edrophonium. The authors speculate the aminophylline, which is a known inhibitor of the enzyme phosphodiesterase, raised the level of c-AMP and, in turn, the level of acetylcholine at the neuromuscular junction and thus antagonized the blocking effect of pancuronium. In addition, the large doses of corticosteroids that the patient had received may have enhanced the release of acetylcholine and further facilitated neuromuscular transmission.