[Effect of rocuronium in sufentanil/isoflurane and sufentanil/propofol anesthesia]

It is a well-known fact that the duration of the effect of non-depolarizing neuromuscular blocking agents is influenced by other anaesthetics. Etomidate, propofol and nitrous oxide have no influence on the duration of effect of rocuronium, but a prolongation of the rocuronium effect under the influence of isoflurane has been described. In this study, we investigated the onset time, duration of effect and recovery index of rocuronium in isoflurane/N2O/sufentanil anaesthesia compared with these parameters in propofol/N2O/sufentanil anaesthesia. Forty patients (10 men and 30 women aged 47.5 +/- 13.0 years, ASA 1-2) were included in the investigation. Anaesthesia was induced by intravenous application of 20 mg etomidate, 0.15-0.2 micrograms/kg sufentanil and 0.9 mg/kg rocuronium. In 20 patients, anaesthesia was supplemented with 0.3-0.8 Vol.% (endexpiratory) isoflurane in a mixture of 30% O2 and 70% N2O (group A). In another 20 patients breathing 30% O2 and 70% N2O propofol (2-6 mg/kg/h) was infused continuously (group B). Onset time, duration of action and recovery index of rocuronium were measured with a nerve stimulator (train-of-four mode). The patients were intubated 60 seconds after completing the rocuronium injection and the intubation conditions were estimated clinically. The onset time amounted to 47.6 +/- 17.8 seconds (group A) and 58.1 +/- 13.6 seconds (group B). In group A, a mean duration of action of 54.3 +/- 13.8 minutes and in group B a mean duration of action of 53.9 +/- 18.9 minutes were measured. The recovery index amounted to 21.2 +/- 10.6 minutes in group A and 17.6 +/- 5.8 minutes in group B. The differences in onset time and recovery times were not significant. Significant changes in arterial blood pressure or heart rate were not observed. The intubation conditions after 60 seconds were excellent in 34 patients (85%) and good in 6 patients (15%). It can be concluded that in comparison with anesthesia maintained by propofol/sufentanil and nitrous oxide/oxygen, the relatively low but necessary supplementation with isoflurane instead of propofol does not lead to a clinically relevant amplification of the relaxing effect of rocuronium.