EEG Correlates of Delayed Emergence after Remimazolam-Induced Anaesthesia Compared to Propofol

Background Delayed emergence from anaesthesia presents clinical challenges, including prolonged stays in the post-anaesthesia care unit (PACU). The neurobiological mechanisms underlying delayed emergence, particularly in remimazolam-induced anaesthesia, remain poorly understood. This study aimed to elucidate these mechanisms by comparing remimazolam and propofol anaesthesia, focusing on prefrontal electroencephalogram (EEG). Methods Patients (age > 18, n = 48) underwent laparoscopic cholecystectomy randomly received remimazolam or propofol general anaesthesia. Power spectrogram analysis and functional connectivity measures, phase lag entropy (PLE) and phase lag index (PLI), were employed to the prefrontal EEG data collected at baseline, unconsciousness, and emergence. Correlation between EEG measures and Patient State Index (PSI) at PACU, as well as time to Aldrete 9, were compared. Results PSI values ( P < 0.0001, P = 0.006) and time to Aldrete 9 at PACU ( P < 0.001) revealed slower recovery in remimazolam-induced anaesthesia. Remimazolam group exhibited residual effects in power at theta ( P = 0.018) and alpha ( Ps < 0.001) bands and lower PLE during emergence in the alpha ( P < 0.0001, P = 0.015) and beta ( P = 0.016, P < 0.001) bands. Delayed consciousness recovery (time to Aldrete 9) under remimazolam was significantly correlated with PLE (Pearson’s r = -.78, P < 0.0001), and PLI (Pearson’s r = .69, P = 0.028) in the alpha band during deep anaesthesia. Conclusion Dynamic changes in prefrontal EEG and the correlation analyses show the potential of EEG in predicting emergence speed, providing insights into the neurobiological mechanisms of short-term delayed emergence in remimazolam anaesthesia.