Onset of neuromuscular blockade and intubating conditions one minute after the administration of rocuronium in children

In a blinded randomized study intubating conditions were compared at one min following intravenous induction with propofol and either suxamethonium 1.0 mg·kg⁻¹, or rocuronium 0.6 mg·kg⁻¹. Onset time to maximal twitch depression, % block at one minute and clinical duration (time to 25% recovery) were measured. Sixty children undergoing elective tonsillectomy were recruited. Onset time [42 s ( SD 11 s)] and clinical duration [3.3 min ( SD 1.0 min)] in the suxamethonium group was significantly ( P <0.001) less than in the rocuronium group [92 s (41 s)] and [24.2 min (6.6 min)] respectively. The median twitch height at one minute for suxamethonium was 0% (range 0–8%) and significantly greater ( P <0.001) at 5% (range 0–22%) for rocuronium. Despite this there was no difference in the intubating conditions at one minute with 25 excellent/5 good in the suxamethonium group and 27 excellent/3 good in the rocuronium group. We conclude that rocuronium 0.6 mg·kg⁻¹ gives optimal intubating conditions at one minute in children.