1. Pain management is a crucial part of general anesthesia surgery. Nociception monitoring can help anesthesiologists better titrate the use of intraoperative analgesic drugs, especially the opioid. 2. Although a variety of nociception monitoring devices have been developed to date, there is not a specific monitoring indicator that serves as the gold standard to objectively guide analgesic management in general anesthesia. 3. The MGRNOX index, which is derived from electroencephalogram (EEG), is used to reflect the correlation between noxious stimuli and opioid analgesics in a state of general anesthesia by converting and quantifying the EEG signals collected by the instrument. However, no studies have so far verified the effect of the MGRNOX index-guided analgesic management of general anesthesia on the consumption of opioids in patients. 4. This study aims to explore the effect of MGRNOX index-guided general anesthesia on opioid consumption in patients undergoing laparoscopic cholecystectomy and the primary hypothesis of our study is that using the MGRNOX index to guide intraoperative pain management during general anesthesia can significantly reduce the consumption of remifentanil during the surgery.