Emergence Delirium (ED) is a common postoperative complication refers to an acute brain dysfunction that occurs during the recovery from general anesthesia, which is mainly characterized by sudden attention and consciousness disorders. The occurrence of ED increases the risk of self-injury, wound dehiscence, accidental catheter dislocation, and postoperative delirium, and is also associated with postoperative cognitive deterioration and increased utilization of medical resources after discharge.

The incidence of hip fracture after surgery in patients over 55 years old is about 45%, and ED is highly predictive of delirium during postoperative hospitalization, which occurs in about 1/3 of ED patients during postoperative hospitalization.

It has been suggested that if delirium is monitored only on the first postoperative day and not at the PACU stage, up to 53% of delirium cases may be missed.

Studies have shown that perioperative application of dexmedetomidine can reduce the risk of postoperative delirium to a certain extent. However, intravenous dexmedetomidine usually leads to problems with delayed extubation, residual sedation, and prolonged PACU stay.

Previous studies have shown that intranasal dexmedetomidine improves perioperative sleep quality and neurocognitive deficits in elderly patients undergoing laparoscopic gynecologic surgery. Compared with intravenous administration, intranasal administration of dexmedetomidine resulted in milder hemodynamic fluctuations. However, stable nasal spray bioavailability is superior to intravenous dosage forms for nasal use.

Based on the above background, this study aims to investigate the effect of nasal spray of dexmedetomidine on the prevention of emergence delirium after total hip replacement in elderly patients.

Inclusion Criteria:

1. Age ≥60 years old
2. Total hip arthroplasty under general anesthesia
3. ASA II-III
4. Informed consent was obtained from patients or their guardians

Exclusion Criteria:

1. Allergy or contraindication to dexmedetomidine
2. Severe rhinitis and nasal deformity
3. Severe bradycardia (heart rate <50 beats/minute) or atrioventricular block of grade 2 or higher, permanent pacemaker implantation, severe heart failure or ejection fraction <30%
4. Patients with previous myocardial infarction, unstable angina pectoris, severe arrhythmia, and cardiac insufficiency
5. Emergency surgery
6. Severe hepatic and renal dysfunction (Child-Pugh class B and C, CKD3-5)
7. Preoperative mental illness, cognitive impairment, and communication difficulties could not be evaluated in the study
8. Preoperative delirium was present