Blinding and randomisation method
In this study, patients were randomly grouped using computer-generated random numbers, and the results of the grouping were kept in sealed opaque envelopes. After obtaining informed consent from the patients, the nurse opened the envelope and divided the patients into either the opioid-sparing anesthesia group (OS group) or the conventional anesthesia group (C group). At the same time the nurse prepared induction medication and intraoperative maintenance medication. Preparation of anesthesia induction medication: 100 mg esketamine and 50 µg sufentanil were configured as 10 ml solution placed in a 10 ml syringe, respectively, and labeled as experimental medication provided to the anesthesiologist in the operating room and given at 0.05 ml.kg-1 during induction. Maintenance drug configuration: In the OS group, 50 mg of esketamine was configured as 50 ml and placed in a 50 ml syringe, and in the C group, 50 ml of 0.9% sodium chloride was placed in a 50 ml syringe, and both were labeled as experimental drugs and provided to the anesthesiologist in the operating room, and intraoperative maintenance was continuously pumped at 0.25 ml.kg-1.h-1. Postoperative follow-up was done by a nurse who was unaware of the grouping. The interoperative anesthesiologists, patients, and postoperative medical staff in this study were unaware of the grouping.