Ultrasound-Guided Cervical Vagus Nerve Block for Postoperative Opioid Consumption After Thoracoscopic Lung Surgery: Study Protocol for a Randomized Controlled Trial.

INTRODUCTION: Effective analgesia after video-assisted thoracoscopic surgery (VATS) remains challenging, as conventional regional techniques mainly target somatic pain but insufficiently address visceral nociception transmitted via the vagus nerve. Cervical vagus nerve block (CVNB) is a novel ultrasound-guided regional technique that may attenuate vagally mediated visceral pain. However, high-quality randomized evidence on its analgesic efficacy and safety after VATS is lacking. This trial aims to evaluate whether adding CVNB to standard thoracic paravertebral block (TPVB) reduces postoperative opioid consumption in patients undergoing VATS lung resection.

METHODS AND ANALYSIS: This randomized, double-blind, placebo-controlled trial will enroll adult patients scheduled for elective VATS. Participants will be randomly assigned (1:1) to receive either 5 mL of 0.375% ropivacaine for CVNB (intervention group) or an equal volume of normal saline (placebo group), in addition to standardized TPVB. The primary outcome is cumulative opioid consumption within 24 hours postoperatively, expressed as intravenous morphine milligram equivalents (MME). Secondary outcomes include postoperative pain scores, time to first rescue analgesia, incidence of nausea and vomiting, quality of recovery, and sleep quality after surgery. A total of 110 patients are required to detect a clinically meaningful reduction in opioid consumption.

ETHICS AND DISSEMINATION: The study was approved by the Ethics Committee of Beijing Chaoyang Hospital (2025-ke-16) and has been registered on www.chictr.org.cn. Results will be disseminated through peer-reviewed journals and academic conferences. This study will be conducted in accordance with the principles of the Declaration of Helsinki.

TRIAL REGISTRATION NUMBER: Chinese Clinical Trial Registry: ChiCTR2500096880.