Atracurium Resistance in a Critically Ill Patient

Abstract

A previously healthy 25‐year‐old man with metastatic testicular teratocarcinoma became resistant to atracurium‐induced neuromuscular blockade as evidenced by train‐of‐four (TOF) monitoring combined with clinical assessment. Subsequently he had an adequate response with a standard dosage of pancuronium. During the first 10 days of neuromuscular blockade, the atracurium requirements escalated from 0.31 to 1.7 mg/kg/hour, guided by TOF monitoring, movement, and spontaneous respirations. The infusion was discontinued but later reinstituted. Despite a total atracurium loading dose of 1.4 mg/kg followed by an infusion rate titrated to 1.7 mg/kg/hour, inadequate paralysis persisted. Atracurium was terminated and an intravenous infusion of pancuronium 0.10 mg/kg/hour was started. Over the next 3 days the pancuronium infusion was titrated down to a range of 0.04‐0.06 mg/kg/hour, followed by a maintenance infusion of 0.01‐0.05 mg/kg/hour for 5 days. A pharmacokinetic alteration, such as increased metabolism or elimination, may have caused the atracurium resistance.