EEG signatures at different propofol vs sevoflurane concentrations

Abstract

The depth of anesthesia is contingent upon the concentration of administered hypnotics, but establishing an exact relationship proves challenging, given its variability among individual patients. To elucidate the connection between the depth of anesthesia and hypnotic concentration, we leverage transient EEG patterns specifically, isoelectric suppressions and power distributions within the alpha and delta frequency bands at constant concentrations. Our investigation focuses on two hypnotic: propofol and sevoflurane. In a cohort encompassing children and young adults undergoing general anesthesia, we employ segmentation algorithms to extract a diverse range of spectral representations in EEG profiles. However, as we systematically alter hypnotic concentrations, a consistent trend emerges: heightened hypnotic concentration predominantly aligns with increased delta band power and reduced alpha band power. Notably, the occurrence of isoelectric suppressions is primarily associated with elevated propofol concentrations and infrequently observed with high levels of sevoflurane. Furthermore, we observe a decrease in the maximal power frequency of the alphaband as hypnotic concentrations increase. In summary, this study offers a systematic quantification of EEG patterns corresponding to distinct concentrations of propofol and sevoflurane. These observed patterns contribute to a nuanced EEG representation of brain activity, laying the groundwork for personalized anesthesia strategies.