The Impact of Transcutaneous Auricular Vagus Nerve Stimulation on Postoperative Recovery in Off-Pump Coronary Artery Bypass Grafting Patients

INTERVENTION: Control Group ( Group C):sham stimulation;taVNS stimulation Group ( Group T ):taVNS stimulation; CONDITION: Postoperative cognitive function after off‐pump coronary artery bypass grafting PRIMARY OUTCOME: Incidence of Postoperative Neurocognitive Dysfunction; SECONDARY OUTCOME: Athens Insomnia Scale Score;Inflammatory biomarkers;Postoperative sleep quality; INCLUSION CRITERIA: 1. Patients scheduled for elective off‐pump coronary artery bypass grafting (CABG); 2. Aged between 50 and 70 years, regardless of gender; 3. American Society of Anesthesiologists (ASA) physical status classification II or III; 4. New York Heart Association (NYHA) functional class II or III; left ventricular ejection fraction (LVEF) > 50%; 5. Postoperative admission to the intensive care unit (ICU); 6. Expected postoperative hospital stay > 24 hours.