qCON and qNOX-Guided Sedation Monitoring During Gastrointestinal Endoscopy: A Prospective Observational Preliminary Study

Background: The depth of sedation during gastrointestinal endoscopy is predominantly assessed based on clinical experience due to the absence of a universally recognized objective standard. This study aimed to evaluate the utility of two novel electroencephalography-derived parameters, the quantitative consciousness index (qCON) and the quantitative nociception index (qNOX), for sedation and analgesia monitoring, and to determine the optimal qCON range correlated with optimal procedural stability. Methods: In this prospective observational study, a total of 220 patients scheduled for elective gastroscopy or colonoscopy were enrolled. All patients received propofol and sufentanil for sedation and analgesia according to routine clinical practice. Depth of anesthesia and nociceptive responses were continuously monitored using qCON and qNOX. Hemodynamic parameters, body movement, and coughing were recorded at predefined time points. The primary outcome was defined as optimal procedural stability, characterized by hemodynamic fluctuations within 10% of baseline combined with the absence of body movement or coughing. Results: = 0.716; p < 0.001). The qNOX index demonstrated a more rapid response to noxious stimuli than qCON during recovery phases. Conclusion: The qCON index appears to provide an objective approach to assessing sedation depth in sedated gastrointestinal endoscopy. Our findings suggest that qCON values within the range of 55 to 63 are associated with optimal procedural stability as defined in this study. Combined monitoring with qCON and qNOX may provide complementary information to support a balanced approach to intra-procedural sedation management, thereby potentially enhancing the safety and overall quality of sedation management. Trial Registration: This study was registered at ClinicalTrials.gov (Registration Number: NCT06604156) on April 11, 2024.