Sevofluran verstärkt den maximalen effekt und verkürzt die anschlagzeit von rocuronium bei kindern

Background: In adults, sevoflurane augments the intensity of rocuronium evoked neuromuscular blockade. However, in children effective doses and onset of action of rocuronium have not been reported during sevoflurane anaesthesia. To test in children the hypothesis that sevoflurane speeds the onset and potentiates the degree of rocuronium induced neuromuscular blockade we studied 50 children aged 2-7 years following approval by the local ethics committee. Methods: After induction and maintenance of anaesthesia with either 2% end-tidal sevoflurane in 60% N₂O/O₂ (n=30) or with propofol (3mg·kg^-1 and 10mg·kg^-1h^-1, n=20) and 60% N₂O/O₂ for 17±1 min, we injected either 0.15, 0.22, or 0.3mg·kg^-1 rocuronium and quantified by mechanomyography the evoked (0.1 Hz ulnar nerve stimulation) response of the adductor pollicis muscle. Dose-response relationships of rocuronium under both anaesthetic regimes were assessed using a generalised linear model based on the maximum-likelihood-technique. Data were compared by analysis of covariance, F-test, and Mann-Whitney-U-test as indicated, p < 0.05, mean ±SD, (95% confidence interval). Results: The degree of neuromuscular blockade was greater (p < 0.05) during sevoflurane (estimated ED 50: 0.15 (0.076-0.177) mg·kg^-1) than propofol (ED 50: 0.25 (0.15-0.35) mg·kg^-1) anaesthesia. Furthermore, onset time was significantly faster under sevoflurane/N₂O compared to propofol/N₂O anaesthesia (110±31 versus 230±52s, p < 0.01, after rocuronium 0.3mg·kg^-1). Conclusion: In young children during steady state anaesthesia onset of action of rocuronium is halved and the degree of neuromuscular blockade is markedly augmented during sevoflurane/N₂O anaesthesia compared to propofol.