Priming with rocuronium accelerates neuromuscular block in children: A prospective randomized study

Abstract

Purpose: To determine the effects of a priming technique with respect to onset time and duration of action of rocuronium (1.5 × ED95, 2.0 × ED95) in a pediatric patient population. Methods: Eighty-four children, age one to seven years undergoing elective pediatric surgery, were studied in a randomized controlled trial. Neuromuscular function was assessed by accelerometry in response to single-twitch stimulation to assess onset of neuromuscular block, followed by train-of-four (TOF) stimulation at the wrist every 15 sec. Children were randomly allocated to one of four groups: Groups 1 and 3 received saline placebo, followed one minute later by a single bolus dose of rocuronium 0.45 mg·kg-1 iv (1.5 × ED95) and 0.6 mg kg-1 iv (2.0 × ED95), respectively. Patients in Groups 2 and 4 received an initial dose of rocuronium 0.045 mg·kg-1 iv and 0.06 mg·kg-1 iv, respectively, followed one minute later by rocuronium 0.405 mg·kg-1 and 0.54 mg·kg-1 iv, respectively. Results: Rocuronium priming significantly accelerated the time to maximum rocuronium-induced neuromuscular block when compared to placebo [median (95% confidence interval)]: 122.5 (98-186) vs 92.5 (68-116) sec (1.5 × ED95, Group 1 vs Group 2, P < 0.05) and 85 (60-142) vs 55 (48-72) sec (2.0 × ED95, Group 3 vs Group 4, P < 0.05), respectively. Spontaneous recovery to a TOF-ratio ≥ 0.9 was dose-dependent and not influenced by priming. Conclusion: Priming accelerated the onset of rocuronium in children. A priming interval of one minute and a cumulative dose of rocuronium 1.5 × ED95 resulted in an onset of neuromuscular block comparable to a single dose of rocuronium (2.0 × ED95).