RESUMO
Ten healthy patients and 20 patients with liver dysfunction [9 Child's A, 7 Child's B and 4 Child's C] received a bolus dose of mivacurium chloride 150 mug/kg each. The electromyographic response was monitored throughout anesthesia until recovery of the first twitch of the train-of-four [TOF] [T1/T0] to at least 85% and the TOF ratio [T4:T1] to at least 80%. There was rapid onset of neuromuscular block in Child's A and B patients compared to healthy patients, but this difference was insignificant. While Child's C patients showed significant longer onset time [time to 95% depression] [= 3.2 min.] compared to healthy patients [= 2.4 min.]. There was no correlation between onset variables and plasma cholinesterase activity. Recovery was prolonged in liver dysfunction patients. The times for recovery of T1/T0 to 5% in Child's A, B and C patients were 14.3, 18.7 and 27.3 min., respectively, compared to 10.5 min. in healthy patients. Time to recovery of T4:T1 to 70% were 44.7, 48.3 and 71.3 min. vs 29.1 min. for healthy patients. There was significant negative correlation between plasma cholinesterase activity and all recovery. It was concluded that in patients with mild or moderate liver dysfunction, mivacurium can be used safely, while in patients with severe liver dysfunction mivacurium can be used cautiously and better with monitoring of neuromuscular function