To investigate the efficacy and safety of perioperative Transauricular vagal nerve stimulation in improving Postoperative Delirium in elderly patients undergoing elective surgery Lay the groundwork for a Phase III study.

This study aims to conduct a prospective, randomized controlled clinical trial on the preventive use of Transauricular vagal nerve stimulation(taVNS) to improve the incidence of Postoperative Delirium(POD) in elderly patients undergoing anesthesia surgery. The intervention group will receive taVNS, while the control group will only wear a taVNS stimulator without current stimulation.

Inclusion Criteria:

• Age≥65 years
• Expected operation time≥ 2 hours
• Postoperative hospital stay≥ 4 days
• Sign the informed consent form

Exclusion Criteria:

• Neurosurgery or cardiac surgery
• Emergency surgery within 6 hours of admission
• End-stage disease with an expected survival of < 3 months
• Preoperative severe cognitive dysfunction affected perioperative cognitive function assessment
• Severe sinus bradycardia, AVB of degree II and above, pacemaker placement