G Protein-Biased µ-Opioid Receptor Agonists in the Management of Pain Following Abdominal Surgery in the AICU

INTERVENTION: Oliceridine group:Oliceridine PCA;Sufentanil group:Sufentanil PCA; CONDITION: Acute postoperative pain PRIMARY OUTCOME: NRS score; SECONDARY OUTCOME: Time to First Flatus;Number of PCA Presses;Time to First PCA Press;Proportion of patients requiring rescue antiemetic medication within 24 hours postoperatively.;The incidence of adverse reactions within 24 hours postoperatively, including nausea, vomiting, dizziness, headache, constipation, pruritus, and respiratory depression.;Patient Recovery Quality Score, Postoperative Hospital Stay, and Satisfaction.;Rate of rescue analgesia and total rescue medication dosage within 24 hours after surgery.; INCLUSION CRITERIA: 1. Age > 18 years; 2. ASA class II–III; 3. BMI 18.5–29.9; 4. Patients scheduled to undergo abdominal surgery under general anesthesia; 5. Patients scheduled for postoperative transfer to the AICU for continued care; 6. Receiving postoperative patient‐controlled intravenous analgesia (PCA); 7. Provided written informed consent; 8. Postoperative NRS score >= 4.