Effects of sevoflurane in general anesthesia on EEG power spectrum and anesthesia depth oriented variables

The main subject in this study is to monitor the changes of EEG power spectrum during sevoflurane general anesthesia and to determine the variables which show meaningful changes for anesthetic depth. Sevoflurane has been suggested as a suitable agent for anesthetic induction. The data base was constructed of the records from a total of 25 patients. During the operation blood pressure, heart rate and sevoflurane agent ratio were recorded. Additionally, EEG recordings are taken continuously during the operation. The power spectral density values corresponding 1-50 Hz frequency interval of the selected EEG slices which has 10 seconds of time interval is used. Investigated EEG parameters show correlations with anesthetic depth in sevoflurane anesthesia. This study confirms EEG power spectrum as potantially useful measures of anesthetic depth in sevoflurane anesthesia. After the induction of sevoflurane, power spectrum of EEG is changed sharply. Total power and low frequency powers are increased sharply. But the beta and gamma band frequencies are decreased totally.