Comparison of sevoflurane–nitrous oxide anaesthesia with the conventional intravenous–inhalational technique using bispectral index monitoring

Ninety-one patients were randomly allocated to one of two groups. Group A was induced with a single vital capacity breath of 6% (end-tidal) sevoflurane in nitrous oxide-oxygen (2 : 1 l.min-1), whereas group B was induced with intravenous fentanyl 1 microg.kg-1 + propofol 2 mg.kg-1 followed by nitrous oxide-oxygen (2 : 1 l.min-1) and sevoflurane. Induction was considered to have been achieved when the bispectral index value decreased to below 70. Mean induction time in group A (95.2 s, 95% CI 88.5-101.9 s) was longer than group B (70.3 s, 95% CI 66.3-74.3 s; p < 0.0001). Mild coughing was more common in group A, but relative hypotension was more common in group B. There was no difference in the emergence times. Thirty minutes after emergence, there was no difference in the incidence of adverse effects, with the exception of essentially mild abdominal pain which was more frequent in group A.