Effect of Transcutaneous Auricular Vagus Nerve Stimulation on the Incidence of Postoperative Delirium in Elderly Patients with Diabetes Undergoing Orthopedic Surgery

INTERVENTION: Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) Group:Transcutaneous Auricular Vagus Nerve Stimulation (taVNS);Sham Stimulation Group:Sham Stimulation; CONDITION: Postoperative delirium (POD) PRIMARY OUTCOME: Postoperative Delirium (POD); SECONDARY OUTCOME: Inflammatory Stress Markers;Sleep Quality;Postoperative Pain and Adverse Events;Perioperative Glycemic Control;Anxiety and depression (HADS); INCLUSION CRITERIA: 1. Age = 65 years, meeting the definition of elderly patients; 2. Previously diagnosed with type 2 diabetes, with blood glucose basically under stable control; 3. Planned to undergo elective orthopedic surgery under general anesthesia (such as hip replacement, fracture internal fixation, etc., with an expected surgery duration of 1‐5 hours); 4. Meets the PACU admission criteria postoperatively; 5. Patient and family are informed and have signed the informed consent form.