Anesthetic Sparing Effects of Dexmedetomidine During Craniotomy: a Retrospective Propensity Score Matching Comparison Between Encephalographic Spectrogram-guided and Processes Encephalographic Index-guided Protocol

The bispectral index (BIS), is widely applied to maintain anesthetic depth. However, this processed EEG index may be ambiguous when dexmedetomidine is administrated. Because each anesthetic produces distinct brain states that are readily visible in the EEG spectrogram which can be easily interpreted by anesthesiologists, the EEG spectrogram-guided anesthesia is theoretically beneficial to avoid unnecessary anesthetic exposure when dexmedetomidine is co-administrated but this remains not yet clarified. Recently, the investigators reported a randomized controlled trial which revealed that co-administration of dexmedetomidine with propofol by using the BIS score guidance, is associated with profound propofol sparing effects and more favorable postoperative neurological outcomes (Eur J Anaesthesiol . 2021 Dec 1;38(12):1262-1271.). Based on the advance of knowledge of EEG spectrogram, the investigators have transited our practice based on the EEG spectrogram guidance. In this study, the investigators analyze the influence of EEG spectrogram guidance on the propofol sparing effect and the postoperative profile in comparison to patients of our previous BIS-guided protocol.