Electroencephalography/Drug Effects

Lower EEG alpha band power is currently extensively studied as a potential biomarker of brain vulnerability. No previous study has evaluated whether there was a difference in EEG power spectrum ranges between propofol and sevoflurane, the two main anesthetic agents for maintenance of general anesthesia, in order to define a cut-off value for the prediction of a higher risk of postoperative delirium. * Primary objective: comparison of EEG alpha power (dB) during maintenance of anesthesia with propofol and sevoflurane using data available in the NeuroSense® depth-of-anesthesia monitoring * Secondary objectives: comparison of other EEG frequency bands during maintenance of anesthesia with propofol and sevoflurane using data from the NeuroSense® depth-of-anesthesia monitoring