Effect of transcutaneous auricular vagus nerve stimulation on postoperative depression in patients with breast cancer and preoperative depressive symptoms: a prospective, randomized controlled study

INTERVENTION: taVNS group:Percutaneous auricular vagus nerve stimulation (taVNS), using the instrument model tVN501, with a frequency of 20Hz, a pulse width of 500µs, and a current intensity of 4‐6mA, lasts for 30 minutes each time, once on the day of the operation and once on the 1st and 2nd days after the operation. The current rise and fall phases each last for 30 seconds;Control group:False stimulation involves only a 30‐second phase of current increase and a 30‐second phase of current decrease during each treatment, without continuous stimulation; CONDITION: Depression PRIMARY OUTCOME: Proportion of patients with postoperative depression achieving response (=50% reduction in MADRS score from baseline); SECONDARY OUTCOME: MADRS Score;Proportion of patients with postoperative depression achieving remission (MADRS score =11);GAD‐7 Score;PSQI Score;QoR‐15 Score;Postoperative NRS Pain Score;Length of Stay (LOS); INCLUSION CRITERIA: 1. Aged between 18 and 65; 2. ASA Grade I‐III; 3. Mild to severe depressive symptoms (11 points < MADRS < 35 points); 4. Female patients scheduled for unilateral radical mastectomy under general anesthesia; 5. Aware of, agreeing to participate in the trial and signing the written informed consent form.