Comparison of time course of neuromuscular blockade in young children following rocuronium and atracurium

In order to compare the neuromuscular effects following rocuronium 0.6 mg kg⁻¹ and atracurium 0.5 mg kg⁻¹ 30 children aged from 18 to 67 months were studied under the same anaesthetic conditions. After induction of anaesthesia with etomidate and fentanyl, neuromuscular blockade was monitored by recording the electromyographic response of the adductor pollicis muscle to a supramaximal train-of-four (TOF) stimulation of the ulnar nerve at 2 Hz for 2 s at 20-s intervals. Intubation was performed when more than 90% muscle relaxation was achieved, thereafter anaesthesia was maintained with 70% nitrous oxide in oxygen and isoflurane 0.5% end-tidal. Mean onset of action was significantly faster following rocuronium (86±44.9 s) (mean±SD) compared with atracurium (126.3±61.0 s). Clinical duration with rocuronium was 22.8±5.31 min and thus significantly shorter than that of atracurium, which was 31.5±6.01 min. A statistically significant difference between rocuronium and atracurium also had been found for recovery of T₁ to 50%, 75% and 90% as well as for the time taken to a TOF ratio of 70%. The recovery index for rocuronium and atracurium was not significantly different with 9.2±3.43 min and 10.9±2.65 min, respectively. Thus, rocuronium may be more advantageous than atracurium for short-lasting surgical procedures in young children.