Traditional opioid analgesia is a treatment method for moderate to severe pain. However, the use of opioid drugs is not without risks. When treating acute pain, patients may experience hypotension, respiratory depression, hypoxia, nausea and vomiting, irritability, and itching. The purpose of this study is to evaluate the comparison of G protein biased μ - opioid receptor agonist oliceridine and traditional μ - opioid receptor agonist sufentanil in terms of analgesia in patients under general anesthesia.

All patients who met the inclusion criteria were randomly divided into two groups based on the use of postoperative analgesic pumps: the sufentanil group and the oliceridine group. The sufentanil group received a treatment regimen of sufentanil 2 µ g · kg-1; The treatment regimen for the oliceridine group is oliceridine 0.4mg · kg-1. The main postoperative observation indicator is the measurement of total pain intensity difference within 48 hours (SPID-48).

Inclusion Criteria:

1. Age>65 years old
2. ASA Level I-III
3. BMI 18.5-29.9
4. Patients undergoing knee joint surface replacement surgery under general anesthesia
5. Postoperative Patient Controlled Intravenous Analgesia Pump (PCIA) Treatment
6. Possess reading and writing abilities
7. You can sign an informed consent form

Exclusion Criteria:

1. Suffering from chronic pain or mental illness before surgery
2. Unable to communicate due to cognitive impairment or language barriers before surgery
3. Patients who have used opioid drugs three days before surgery
4. Patients with long-term alcohol consumption
5. Abnormal liver and kidney function or dialysis patients
6. Concurrent severe cardiovascular, respiratory, and autonomic neuropathy
7. Participated in clinical studies of other drugs or medical devices in the past 3 months