PROLONGED NEUROMUSCULAR BLOCK FOLLOWING M IVACURIUM

Mivacurium, a new short acting non depolarizing neurornuscular blocker , is metabolized, as suxamethonium, by plasma cholinesterase, Therefor e its duration of action is increased in patients with reduced plasma cholinesterase activity. We report a case of prolonged neuromuscular b lock after an i.v. bolus of mivacurium (0,20 mg . k(-1)) in a 69 year- old ASA II woman with an unrecognized cholinesterase deficiency underg oing a lumbar sympathectomy for arteriopathy of the lower limbs, The d uration of the block was 6 h and plasma cholinesterase concentrations were very low (54% and 610 UI . L(-1)), as well as the dibucaine numbe r (16%), which suggests an homozygous enzymatic deficiency, Mechanical ventilation and sedation were continued until spontaneous return of f ull neuromuscular function.