Effect of Transauricular Vagus Nerve Stimulation on postoperative pain management in Video Assisted Thoracic Surgery: protocol for a randomized controlled clinical trial

Abstract Introduction : Transcutaneous auricular vagus nerve stimulation (taVNS) is a novel pain management technique that has gained popularity in recent years due to its non-invasive nature and ease of operation. Current literature has substantiated its efficacy in managing pain syndromes and chronic pain. However, there is a paucity of evidence regarding its effectiveness in treating acute postoperative pain. This project aims to explore the efficacy of taVNS in postoperative pain management, with a focus on video-assisted thoracic surgery(VATS). Pain scores will be assessed using a visual analogue scale (VAS, 0-100mm) before and after the administration of taVNS, respectively. Methods : This double-blind, single-center, randomized controlled clinical trial aims to enroll 116 patients (n=58) scheduled to undergo VATS (including segmentectomy and lobectomy) under general anesthesia at Peking Union Medical College Hospital. Participants will be divided into an intervention group (receiving taVNS) and a sham intervention group (receiving sham-taVNS), and will undergo a 1-hour intervention on the first postoperative day. The primary outcome is the pain relief rate, defined as a reduction of 15mm or 30% in the VAS (1-100mm) score immediately before and after the intervention on the first postoperative day. Secondary outcomes include: the proportion of patients with inadequate analgesia within three days after intervention; the difference in VAS scores immediately before and after the intervention on the first postoperative day; the specifics and frequency of additional analgesic measures taken by patients from the first to the third postoperative day after intervention; immediate changes in heart rate variability before and after the intervention, based on time-domain and frequency-domain measurements; the difference in RCSQ scores on the night of surgery and the night after intervention; the incidence of taVNS-related adverse effects within three days after intervention. The follow-up period for this study will be three days after surgery. Ethics : Ethical approval of this study has been granted by the Ethics Committee of Peking Union Medical College Hospital, Chinese Academy of Medical Sciences. Informed consent will be obtained from all the participants before enrollment. Trial registration: The trial was registered with ClinicalTrials.gov (registration number: NCT06912399) on March 30, 2025. The registration website is https://register.clinicaltrials.gov.