A MIXTURE OF MIVACURIUM AND ROCURONIUM IS COMPARABLE IN CLINICAL ONSET TO SUCCINYLCHOLINE

Study Objectives: To compare the clinical onset and duration of a comb ination of mivacurium and rocuronium with succinylcholine, and to dete rmine the efficacy of this mixture for rapid tracheal intubation. Desi gn: Observer-blind prospective study. Setting: Teaching hospital. Pati ents: 70 ASA status I and II patients having general anesthesia for el ective surgery. Measurements and Main Results: After induction of gene ral anesthesia patients randomly received succinylcholine 1.0 mg/kg, r ocuronium 0.6 mg/kg or a combination of rocuronium 0.6 mg/kg and mivac urium 0.15 mg/kg. Evoked muscular response at the adductor pollicis wa s measured by mechanomyography. The time from injection of muscle rela xant(s) to ablation of T-1 (clinical onset) and recovery of T-1 to 25% of control height (clinical duration) was recorded. Intubating condit ions 45 seconds after administration of muscle relaxants were assessed . There was no significant difference in clinical onset time between s uccinylcholine (mean +/- SD, 47.4 +/- 6.5 seconds) and the combination of mivacurium-rocuronium (51.2 +/- 13.4 seconds). Intubating conditio ns with mivacurium-rocuronium rocuronium were comparable to those of s uccinylcholine. The clinical duration of rocuronium 0.6 mg/kg (38.9 +/ - 12.3 minutes) was prolonged by the addition of mivacurium (49.0 +/- 9.6 minutes). Conclusions: This combination of mivacurium and rocuroni um is comparable to succinylcholine in both clinical onset time and qu ality of intubating conditions When rapid onset of dense neuromuscular blockade and intermediate clinical duration is desirable, this mixtur e may be an acceptable alternative to succinylcholine.