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 [42s (SD 11s)] 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 [92s (41s)] 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.