Intubating conditions and neuromuscular effects of mivacurium during propofol-alfentanil anaesthesia

In three groups of 20 patients, anaesthetized with propofol and alfentanil, tracheal intubation conditions and the onset of neuromuscular blockade after administration of three different doses of mivacurium chloride (0.11, 0.15, and 0.19 mg/kg = 1.5 x ED95, 2 x ED95, and 2.5 x ED95) were assessed. Intubation conditions were found to be clinically acceptable (good or excellent) in 83% of patients. Eighty-two per cent of patients were successfully intubated on the first attempt after 60-90 s. No difference in intubation scores or number of intubation attempts among the three dosage groups were found. We conclude that mivacurium chloride allows smooth intubation in most patients within 60-90 s, even with the lowest dose (0.11 mg/kg), after a propofol-alfentanil induction of anaesthesia. However, because there were a few patients in whom intubating conditions were inadequate at 60-90 s, we are reluctant to advocate the preference of mivacurium chloride over suxamethonium for rapid sequence induction in emergency situations.