Evaluation of Intraoperative Awareness and Its Correlation With Processed EEG Biomarkers During Laparoscopic Surgery

This prospective observational cohort study aims to evaluate intraoperative responsiveness and possible intraoperative awareness in adult patients undergoing elective laparoscopic abdominal surgery under general anesthesia and to investigate their relationship with processed electroencephalography (EEG) biomarkers. Approximately 600 patients will be enrolled. Preoperative assessment will include the 15-item Quality of Recovery questionnaire (QoR-15), State-Trait Anxiety Inventory (STAI), Mini-Mental State Examination (MMSE), and Beck Anxiety Inventory (BAI). Processed EEG monitoring will be performed using the Masimo SedLine system. The system will be applied before induction of general anesthesia and maintained throughout the anesthetic period until extubation. Patient State Index (PSI) values will be recorded at 5-minute intervals from the beginning of surgery until extubation. The isolated forearm technique (IFT) will be performed five times during predefined stages of anesthesia and surgery. The fifth assessment will be performed at any stage of surgery when there is clinical or processed EEG evidence suggesting possible awakening, including a PSI value above 50 and/or accompanying hemodynamic changes such as tachycardia or hypertension. Postoperative assessment will be performed at the 24th postoperative hour and at the second postoperative week. At 24 hours, QoR-15 and structured awareness questioning will be performed. At two weeks, QoR-15, Beck Anxiety Inventory, dream recall, and further assessment of possible intraoperative awareness will be performed. The study will investigate the relationship between PSI changes, isolated forearm technique responses, and postoperative reports suggestive of intraoperative awareness.