INTUBATING CONDITIONS AND ONSET OF ACTION AFTER ROCURONIUM, VECURONIUM, AND ATRACURIUM IN YOUNG-CHILDREN

To evaluate muscle relaxant onset times and tracheal intubating condit ions, 60 children (ASA physical status I or II) aged 18 to 72 mo were randomly assigned to receive a bolus of either rocuronium 0.6 mg/kg, v ecuronium 0.1 mg/kg, or atracurium 0.5 mg/kg. After induction of anest hesia with etomidate 0.2-0.4 mg/kg and fentanyl 1-3 mg/kg, lungs were ventilated with 50% nitrous oxide in oxygen via a face mask. The evoke d electromyogram of the adductor pollicis to a train-of-four stimulati on every 20 s was monitored. After administration of the muscle relaxa nt, endotracheal intubation was attempted every 30 s, beginning 30 s a fter drug administration, until intubation could be achieved with good or excellent conditions. Rocuronium produced acceptable intubating co nditions significantly faster (all tracheas intubated within 60 s) com pared with vecuronium (120 s) and atracurium (180 s). The quality of i ntubating conditions at the time of completed intubation was rated sig nificantly better with rocuronium than with vecuronium or atracurium. However, onset to 95% block at the adductor pollicis muscle was not si gnificantly different alter rocuronium (92 +/- 46.9 s), vecuronium (11 2 +/- 33.3 s), or atracurium (134 +/- 57.1 s), and mean neuromuscular block achieved ai the point of successful intubation was not complete in all groups. We conclude that clinically acceptable intubating condi tions are produced more rapidly with rocuronium than with atracurium o r vecuronium.