Comparing the Effectiveness of S-Ketamine Combined with Sufentanil versus Sufentanil Alone for Postoperative Pain Management in Elderly Patients Undergoing Laparoscopic Radical Resection of Gastrointestinal Cancer: A Randomized Controlled Trial

Background. The optimal analgesic dose of S-ketamine after laparoscopic gastrointestinal malignancy surgery remains unclear. This study aimed to evaluate the effect of S-ketamine combined with sufentanil in patient-controlled intravenous analgesia (PCIA) on postoperative pain relief in elderly patients undergoing laparoscopic surgery for gastrointestinal tumors. Methods. Elderly patients undergoing laparoscopic radical resection of gastrointestinal cancer were randomly assigned to one of three postoperative analgesia groups: F group received 2 ug/kg sufentanil in PCIA, LSF group received 0.5 mg/kg S-ketamine and 1.5 ug/kg sufentanil, and SF group received 1 mg/kg S-ketamine and 1 ug/kg sufentanil. The PCIA also contained 0.15 mg/kg of butorphanol and 0.02 mg/kg of ramosetron. Study drugs were administered via PCIA for 48 hours postoperatively. The primary outcome was the accumulated parecoxib sodium requirements within 48 hours after surgery. Results. A total of 105 patients were randomized, and 95 completed the trial (F group: n = 32, LSF group: n = 32, and SF group: n = 31). The cumulative consumption of parecoxib sodium within 48 hours postoperatively was lower in the SF group compared to that in the F group (median difference: −40 mg; 95% confidence interval: −40 to 0; P=0.0028). The number of PCIA compressions within 48 hours after surgery was smaller in the SF group compared to that in the F group. NRS pain scores at 6 h and 12 h postoperatively were reduced in the SF group compared to that in the F group, both at rest and during movement. Compared to the F group, the incidence of postoperative mild depression was lower, the time to first flatus and time to first defecation were shorter, and the incidence of postoperative vomiting was lower in the SF group. The mechanical pain threshold, hyperalgesia area, and sedation scores were similar between the SF and F groups. No differences were observed in the abovementioned parameters between the LSF group and the F group. Conclusion. This trial demonstrated that 1.0 mg/kg S-ketamine combined with 1 ug/kg sufentanil in PCA decreased cumulative parecoxib sodium consumption within 48 hours after laparoscopic radical resection of gastrointestinal cancer in elderly patients.