Efficacy and Safety of Anrikefon Injection for the Treatment of Postoperative Pain in Patients Undergoing Totally Laparoscopic Radical Distal Gastrectomy

• Anruikefen (Intravenous Bolus) (Drug): Anruikefen 1 μg/kg via intravenous bolus injection, once every 8 hours (q8h), for a total of 6 doses.
• Anruikefen (Intravenous Infusion) (Drug): Anruikefen 1.5 μg/kg via intravenous infusion, once every 8 hours (q8h), for a total of 6 doses.
• Placebo Group (Drug): Normal Saline administered via intravenous bolus injection, once every 8 hours (q8h), for a total of 6 doses.

Primary outcomes

• Total Consumption of Sufentanil via PCIA [within 48 Hours after the First Administration Postoperatively]

Secondary outcomes

• Cumulative consumption of sufentanil delivered via patient-controlled intravenous analgesia (PCIA) [From the end of surgery up to 24 hours after the first administration of study drug]
• Rest numerical rating scale (NRS) pain score assessed at baseline, 1 hour , 8 hours , 24 hours, and 48 hours after the first study drug administration; [Baseline (immediately before the first study drug administration), 1 hour ± 30 minutes, 8 hours ± 2 hours, 24 hours ± 2 hours, and 48 hours ± 2 hours after the first administration of study drug]
• Dynamic numerical rating scale (NRS) pain score assessed at baseline, 1 hour , 8 hours , 24 hours, and 48 hours after the first study drug administration; [Baseline (immediately before the first study drug administration), 1 hour ± 30 minutes, 8 hours ± 2 hours, 24 hours ± 2 hours, and 48 hours ± 2 hours after the first administration of study drug]
• Peak rest numerical rating scale (NRS) pain score [Within the period from 0 hours to 24 hours after the first administration of study drug]
• Peak dynamic numerical rating scale (NRS) pain score [Within the period from 0 hours to 24 hours after the first administration of study drug]
• Incidence of rescue antiemetic treatment administration [Within 48 hours after the first administration of study drug]
• I-FEED score [At 24 hours, 48 hours, 72 hours, and 96 hours after the first administration of study drug]
• Time in hours from the end of surgery to the first oral intake [Throughout the inpatient hospital stay after surgery]
• Time in hours from the end of surgery to the recovery of bowel function (defined as the first passage of flatus or first defecation) [Throughout the inpatient hospital stay after surgery]
• Levels of inflammatory factors (IL-6, IL-10, TNF-α, CRP, NLR) [Preoperative baseline (prior to surgery), before the first postoperative administration of study drug, and 48 hours after the first administration of study drug]
• Sleep quality （assessed via the Richards-Campbell Sleep Questionnaire） on the night of the first study drug administration [On the single night following the first administration of study drug]
• Time (hours) from the end of surgery to the first out-of-bed ambulation [Throughout the inpatient hospital stay following surgery]
• Total time (days) from surgery until patients meet discharge criteria [during hospitalization]
• Total hospital length of stay measured in calendar days at the time of participant discharge after surgery [At the moment of hospital discharge for each participant]
• Patient satisfaction score at 48 h after the first study drug administration [At 48 hours after the first administration of study drug]
• Overall patient recovery quality score evaluated via the QoR-15 questionnaire [At 24 hours, 48 hours, and 72 hours after the first administration of study drug]
• Incidence of Serious Adverse Events (SAEs) [Throughout the inpatient hospital stay following surgery]
• Incidence of Treatment-Emergent Adverse Events (TEAEs) related to the study drug [Throughout the inpatient hospital stay following surgery, during the period of study drug administration]

Sex: All, ages: 18 Years to 75 Years

Inclusion Criteria:

* Aged between 18 and 75 years old (inclusive).
* American Society of Anesthesiologists (ASA) physical status classification Class I-III.
* Body Mass Index (BMI) ranging from 18 kg/m² to 30 kg/m² (inclusive).
* Patients scheduled for elective total laparoscopic distal gastrectomy for gastric cancer under general anesthesia, with surgical duration < 5 hours.
* Surgical incision length < 8 cm.
* Voluntarily agree to participate in the trial and sign the informed consent form.

Exclusion Criteria:

* Patients undergoing emergency surgery or suffering from trauma.
* Patients who undergo conversion to open surgery or laparoscopically assisted distal gastrectomy for gastric cancer during the operation.
* Patients who refuse to receive Patient-Controlled Intravenous Analgesia (PCIA).
* Patients with a history of prior abdominal surgery.
* Patients expected to require prolonged endotracheal intubation after surgery.

• Han Liang, MS, Principal investigator, Tianjin Medical University Cancer Institute and Hospital