Nociception is the encoding and processing of noxious stimulation and is considered an objective indicator for monitoring pain. Currently, a new clinically-applied medical-engineering integrated monitoring device for noxious stimulation response has emerged. Its fundamental principle is based on the monitoring of electroencephalographic (EEG) activity, incorporating two monitoring parameters: the quantitative consciousness (qCON) index and the quantitative nociceptive (qNOX) index. However, in the context of sedation for gastrointestinal endoscopy, how the dynamic changes of the quantitative consciousness index (qCON) and the quantitative nociception index (qNOX) reflect the depth of sedation and nociceptive response remains unclear. Safe and effective sedation monitoring includes both direct visual monitoring and physiological monitoring, that is, monitoring the patient's hemodynamics and depth of sedation. This study utilizes qCON and qNOX monitoring to assess the sedation and analgesic states of patients undergoing painless gastroenterological endoscopy. By combining visual assessment (cough reflex, respiratory depression, and limb movement) with clinical physiological monitoring (vital signs monitoring and pulse oximetry), the aim is to explore the optimal sedation range for gastrointestinal endoscopy under sedation, providing new anesthesia monitoring tools for clinical use.