Postoperative delirium is a delirium that occurs within 7 days after surgery or before hospital discharge. It has been shown that combined POD can increase the incidence of postoperative pulmonary infections, deep vein thrombosis and decubitus ulcers, and increase the incidence of disability and mortality. The incidence of postoperative delirium in geriatric orthopedics is high.

Investigators conduct a prospective clinical study on geriatric orthopedic surgery patients to investigate the effect of oxytocin nasal spray on the prevention of postoperative delirium in geriatric orthopedic surgery. Cases were included according to the inclusion and exclusion criteria, and induction, maintenance and resuscitation were performed according to the standard protocol for general anesthesia. Before the end of surgery, the Investigators administered oxytocin nasal spray (Oxytocin) that was 3 sprays in each nostril (4 IU each) for a total of 24 IU. Beginning 1 day postoperatively, administer 24 IU of oxytocin nasal spray 2 times/day in the morning and in the evening. Until 7 days after surgery or discharge. The sample size are 77 cases in phase I and 143 cases in phase 2, total 220 cases.

Elderly patients undergoing orthopedic surgery under general anesthesia

Inclusion criteria:

1. Age ≥ 65 years;
2. Patients who were to undergo elective orthopedic surgery under general anesthesia with tracheal intubation;
3. ASA class I-III;
4. Estimated duration of surgery ≥ 1 hour; (5) The patient himself/herself or his/her legal representative;
5. Informed consent from the patient or legal representative;
6. Proficiency in the use of Chinese language for communication.

Exclusion criteria:

1. Nasal cavity occupation, patients with fillers in the nose

2. Oxytocin allergy;

3. Patients with previous psychiatric and neurological disorders, such as depression, severe central nervous system depression, Parkinson's disease, basal ganglia disease.

   Goldson's disease, basal ganglia lesions, schizophrenia, epilepsy, Alzheimer's disease, myasthenia gravis, and so on;

4. Pregnant and lactating women

5. Patients with severe hepatic insufficiency (Child-Pugh class C);

6. patients with severe renal insufficiency (dialysis is required before surgery)

7. Severe heart failure (METS<4);

8. Preoperative inability to communicate (coma or dementia);

9. Severe preoperative blindness, deafness, or inability to understand Mandarin to complete preoperative delirium screening;

10. Preoperative cognitive impairment as determined by a MoCA evaluation prior to surgery;

11. Patients who are scheduled for 2 surgeries within 7 days of surgery;

12. Patients with bone malignancy

13. Currently participating in other clinical trials.