Intramuscular rocuronium in infants and children - A multicenter study to evaluate tracheal intubating conditions, onset, and duration of action

Background: This multicenter, assessor-blinded, randomized study was done t o confirm and extend a pilot study showing that intramuscular rocuronium ca n provide adequate tracheal intubating conditions in infants (2.5 min) and children (3 min) during halothane anesthesia. Methods: Thirty-eight infants (age range, 3-12 months) and 38 children (age range, 1 to 5 yr) classified as American Society of Anesthesiologists phys ical status 1 and 2 were evaluated at four investigational sites. Anesthesi a was maintained with halothane and oxygen (1% end-tidal concentration if < 2.5 yr; 0.80% end-tidal concentration if > 2.5 yr) for 5 min. One half of the patients received 0.45 mg/kg intravenous rocuronium. The others receive d 1 mg/kg (infants) or 1.8 mg/kg (children) of intramuscular rocuronium int o the deltoid muscle. Intubating conditions and mechanomyographic responses to ulnar nerve stimulation were assessed. Results: The conditions for tracheal intubation at 2.5 and 3 min in infants and children, respectively, were inadequate in a high percentage of patien ts in the intramuscular group. Nine of 16 infants and 10 of 17 children had adequate or better intubating conditions at 3.5 and 4 min, respectively, a fter intramuscular rocuronium. Better-than-adequate intubating conditions w ere achieved in 14 of 15 infants and 16 of 17 children given intravenous ro curonium. Intramuscular rocuronium provided greater than or equal to 98% bl ockade in 7.4 +/- 3.4 min (in infants) and 8 +/- 6.3 min (in children). Twe nty-five percent recovery occurred in 79 +/- 26 min (in infants) and in 86 +/- 22 min (in children). Conclusions: Intramuscular rocuronium, in the doses and conditions tested, does not consistently provide satisfactory tracheal intubating conditions i n infants and children and is not an adequate alternative to intramuscular succinylcholine when rapid intubation is necessary.