Gastrointestinal dysfunction is common in patients after major surgery, especially for neurosurgery. It was reported 80% of neurosurgery patients could be combined with gastrointestinal dysfunction, and it may relate to old age, surgery time, and factors of anesthesia and surgery. Meanwhile, postoperative constipation, nausea, and vomiting induced by gastrointestinal dysfunction may increase the intracranial bleeding. Oliceridine could activate mu opioid receptors without the interaction of (beta)arr2-muOR, and may reduce the gastrointestinal dysfunction, but a limited study has illustrated this topic. Thus, this study is conducted to explore whether oliceridine could reduce the gastrointestinal dysfunction vs. sufentanil in patients undergoing neurosurgery.

Inclusion Criteria:

• Patients undergoing selective neurosurgical resection of craniocerebral tumors;
• Age ≥ 18 years old;
• American Society of Anesthesiologists (ASA) grade 1-3;
• Sign the informed consent form.

Exclusion Criteria:

• Patients unable to complete scale assessment due to preoperative language dysfunction or communication impairment;
• Patients with preoperative symptoms of posterior cranial nerve injury and who need to retain a tracheal tube;
• Patients with insular, brainstem, or medullary lesions that may impair early postoperative recovery of consciousness;
• Patients undergoing intracranial lesion resection via the transsphenoidal approach;
• Patients with a history of previous abdominal surgery;
• Patients with BMI > 35.0 kg/m2;
• Patients with liver or kidney dysfunction;
• Patients with a history of allergic or adverse reactions to the test drug;
• Patients with a history of drug abuse;
• Pregnant or lactating women.