· To explore the effect of intraoperative continuous remifentanil infusion at the 0.05?0.15 μg/(kg·min) dosage on postoperative analgesia after gastrointestinal surgery.

· The patients received patient-controlled intravenous analgesia (PCIA) after elective gastrointestinal surgery from April to December 2019 in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine were included in this retrospective analysis. They were divided into remifentanil group (n=360) and control group (n=335) according to whether the patients were treated with intraoperative continuous pumping of remifentanil at the 0.05?0.15 μg/(kg·min) dosage. Propensity score matching (PSM) was used to compare the difference of postoperative analgesic remedy and the pressing of patient-controlled analgesia (PCA) between the two groups.

· By using a 1∶1 PSM analysis, 286 couples of patients were matched successfully. In the remifentanil group, the proportion of patients receiving postoperative analgesic remedies was significantly less than that in the control group (32.5% vs 40.9%, P=0.037). Compared with the control group, the remifentanil group had a lower risk of poor analgesic effect and necessity of postoperative analgesic remedies (RR=0.696, 95%CI 0.495?0.980). There was no significant difference in the total PCA pressing times between the remifentanil group and control group [5 (1, 12) vs 5 (1, 13), P=0.568], but in the remifentanil group, the proportion of patients with PCA pressing times > 13 was less than that of the control group (21.3% vs 24.5%).

· Continuous pumping of remifentanil at the 0.05?0.15 μg/(kg·min) dosage in elective gastrointestinal surgery is helpful to decrease postoperative analgesic demand. The patients receiving intraoperative remifentanil infusion at a low dosage has a lower risk in requiring postoperative analgesic remedies, compared with patients who do not receive intraoperative remifentanil infusion.