British Journal of Anaesthesia 1992; 69: 29-35 FACTORS AFFECTING MAGNITUDE AND TIME COURSE OF NEUROMUSCULAR BLOCK PRODUCED BY SUXAMETHONIUM

This study was designed to identify factors that significantly alter the magnitude and duration of suxamethonium-induced neuromuscu/ar block in patients with an apparently normal genotype for pseudocholinesterase. One hundred and fifty-six adults (ages 18-65 yr) were allocated to 13 subgroups. Patients in each subgroup received suxamethonium 50-2000 ug kg-'. The mechano-graphic response of the adductor pollicis brevis muscle to ulnar nerve stimulation was recorded. The ED so was found to be 167 fig kg'1, EDX was 316 ng kg-1 and EDgs was 392 fig kg-'. The dur-ation of action (AX) was in agreement with earlier published results. The magnitude of block was dose-related and decreased with increasing onset time (ton) and pseudocholinesterase activity (PChA). Neither age nor gender affected the degree of suxamethonium-induced block. Ax was dose-related, decreased with increasing PChA, and was shorter for women. Age and Xon had no effect on Ax