[Quantitative analysis of electroencephalographic (EEG) activity during sevoflurane anesthesia]

The change in electroencephalographic (EEG) activity during sevoflurane anesthesia was quantitatively evaluated by using zero-crossing analysis in 10 adult patients. The deceleration of EEG activity was significant and dose-dependent. Such change was not significantly different among the regions. Burst suppression appeared at 2-2.5 MAC in all patients. The significant decrease in both alpha and beta activities and the significant increase in delta activity disappeared with 1% or less of sevoflurane. Toward the emergence from anesthesia, EEG activity accelerated and there was no significant difference in its activity between the emergence period and control period. The results demonstrated that the effect of sevoflurane on EEG activity is similar to that of other inhalation anesthetics, but the difference among anesthetics should be clarified in a further study.