Effects of Auricular Vagus Nerve Stimulation Combined with Music Therapy on Perioperative Stress and Recovery Quality in Lower Limb Surgery Patients: A Randomized Controlled Trial

INTERVENTION: Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) Group:Upon admission to the PACU after surgery, patients received a single 30‐minute session of transcutaneous auricular vagus nerve stimulation.;Music Therapy Group:Patients received a single 60‐minute session of standardized soothing music played in the PACU, with the intervention duration matched to that of the taVNS group.;Blank Control Group:Patients wore simulated electrodes and remained resting in a supine position for 60 minutes.; CONDITION: Acute Perioperative Stress PRIMARY OUTCOME: cortisol variation from T1 to T2; SECONDARY OUTCOME: Changes in ACTH (Adrenocorticotropic Hormone);Changes in IL‐6 (Interleukin‐6);Changes in a‐amylase;Changes in blood glucose;Changes in HRV (Heart Rate Variability);Changes in LF/HF ratio (Low‐Frequency/High‐Frequency ratio);Fluctuations in vital signs;Intraoperative dosages of sedatives and analgesics; INCLUSION CRITERIA: 1. Aged 18 to 65 years. 2. Scheduled for elective lower limb surgery. 3. American Society of Anesthesiologists (ASA) physical status I–II; meeting the indications for neuraxial anesthesia. 4. Able to understand the study protocol and provide written informed consent. 5. Capable of cooperating with blood sampling and scale/ questionnaire assessments at the intraoperative stress peak and after the intervention.