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

Abstract

SummaryNinety-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 21 ), whereas group B was induced with intravenous fentanyl 1 mg.kg 21 1 propofol 2 mg.kg 21 followed by nitrous oxide±oxygen (2 : 1 l.min 21 ) 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.

Effects of subanaesthetic and anaesthetic doses of sevoflurane on regional cerebral blood flow in healthy volunteers. A positron emission tomographic study

“…Impedance was kept below 5 k. Electroencephalography spectral analysis was performed in periods of artefactfree EEG (see below) with Fast Fourier Transform algorithm calculation power values of delta (0.1-4.0 Hz), theta (4-8 Hz), alpha (8)(9)(10)(11)(12), and beta bands (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). Sixteen tin-cup electrodes (Medtronis Functional diagnostics A/S, Skovlunde, Denmark) were placed across the scalp according to the 10-20 International System supplemented by the two linked-ears reference.…”

“…On the screen it displays an active (moving) analogue waveform and a numerical value, the BIS value, which is updated every 2 s. The BIS value, a measure of the hypnotic effects of anaesthetics, ranges from 0 to 100 (95-100 when the patient is awake, 80 with light hypnotic effects, 70 with moderate hypnotic effects, 60 indicating unconsciousness and 40 with deep hypnotic effects) (18). This module acquires and processes realtime EEG data into one channel.…”