The Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Perioperative Anxiety for Patients Undergoing Thyroid Surgery

INTERVENTION: T group:Transcutaneous Auricular Vagus Nerve Stimulation;S group:sham stimulation; CONDITION: Perioperative anxiety PRIMARY OUTCOME: state‐trait anxiety inventory score; SECONDARY OUTCOME: Amsterdam preoperative anxiety and information scale score;Athens insomnia scale score;visual analog scale score;vital signs;types and dosage of analgesics;operation time,surgical manner,anesthesia duration and intraoperative volume.;time of first anal exhaust after operation;postoperative hospital stay; INCLUSION CRITERIA: 1.Patients undergoing elected thyroid surgery and general anesthesia with tracheal intubation; 2.Ages between 18 and 65; 3.No serious systemic disease, ASA grade I II; 4.No contraindication for the use of vagus nerve stimulator; 5.Agree to participate in this study and sign the informed consent form.