Surgical Pleth Index and Exploratory EEG-Derived Composite Index for Intraoperative Analgesia Monitoring During Hysterectomy: A Retrospective Analysis

This retrospective study demonstrated the feasibility of deriving open-source EEG-derived composite and SPI-surrogate indices from routinely recorded physiological signals. The Exploratory EEG-derived composite index showed an expected correlation with its BIS component and moderate associations with remifentanil concentration and blood pressure, representing exploratory physiological associations rather than validated measures of intraoperative nociception.