A comparison between mivacurium and suxamethonium in children

Abstract

The neuromuscular effects of mivacurium were compared with those of suxamethonium in 69 children (aged 2-12 years), during nitrous oxide, oxygen and halothane anaesthesia in a randomised open study. Neuromuscular block was monitored by measuring the acceleration of the thumb caused by contraction of the adductor pollicis muscle after supramaximal stimulation of the ulnar nerve at the wrist using an Accelograph. End-tidal carbon dioxide was maintained at about 4 kPa in both groups. The mean times (95% confidence intervals) for T1:T0 ratio to decrease to 75%, 50%, 25% and 5% of control values were 50 (42-59), 62 (52-74), 83 (68-100) and 93 (46-108) s respectively for mivacurium and 18 (15-22), 26 (22-30), 32 (28-37) and 43 (38-49) s respectively for suxamethonium. The times for T1:T0 ratio to recover to 25%, 50% and 70% of control values were 615 (542-698), 769 (687-859) and 901 (820-993) s respectively for mivacurium and 196 (179-214), 216 (201-234) and 242 (216-259) s respectively for suxamethonium. The range of maximum block was similar for both drugs. The average time to reach maximum block was 143 s for mivacurium and 56 s for suxamethonium. Intubating conditions were similar in the two groups.