Abstract:Objective To explore the effects of different administration timings of esketamine before skin incision and during abdominal closure on postoperative gastrointestinal function，pain levels and serum indexes in gastric cancer patients. Methods This prospective study included 94 gastric cancer patients who underwent laparoscopic surgery at the Second Affiliated Hospital of Hainan Medical University from January 10，2022 to March 30，2023. They were randomly divided into control group，group A，and group B based on computer codes. After excluding 2 cases in both groups A and B，each group had 30 cases，respectively. The patients in the control group were infused with equal volume of physiological saline before and during abdominal closure. Group A received intravenous infusion of esketamine before incision and physiological saline during abdominal closure. Group B was infused with physiological saline before skin incision，and esketamine at abdominal closure. The dosage of administration for both group A and group B was 0.4 mg/kg. Surgical and anesthesia indicators，postoperative gastrointestinal function indicators，pain levels［the degree of pain was assessed using the Visual Analogue Scale（VAS）at 4 hours postoperatively（T1），8 hours postoperatively（T2），24 hours postoperatively（T3），and 48 hours postoperatively（T4）］，and serum indexes among three groups were compared. Results There was a statistically significant difference in the anesthesia recovery time among group A，group B，and the control group［（10.56±1.51）min，（13.05±1.02）min，（9.86±1.15）min，F=54.489，P <0.01］. The anesthesia recovery time of group A and the control group was shorter than that of group B（P<0.05），while there was no statistically significant difference in surgical time and intraoperative bleeding among the three groups（P>0.05）. There was no statistically significant difference（P>0.05）between group A and group B in the time of first postoperative exhaust，defecation，eating，and recovery of bowel sounds，but both groups were significantly shorter than the control group（P<0.05）. Compared to T1，the VAS scores at T2-T4 were higher in all three groups（P<0.05）. The VAS scores of group A at T2 and T3 were higher than those of group B，with statistical significance（P<0.05）. The VAS scores of group A and group B at T2 - T4 points were both higher than those of the control group（P<0.05）. Levels of interleukin（IL）-6，IL-10，and C-reactive protein（CRP）in group A were significantly lower than those in group B and control group 24 h postoperatively，while levels of IL-6，IL-10，and CRP in group B were significantly lower than those in the control group（P<0.05）. Conclusion There was no significant difference in the effect of using esketamine before and after abdominal closure on postoperative gastrointestinal function in patients undergoing gastric cancer surgery. However，compared to administration of anesthesia during abdominal closure，administration of anesthesia before skin incision can reduce the levels of inflammatory factors in patients and shorten the time of anesthesia recovery.