Effects of Different Frequencies of Transauricular Vagus Nerve Stimulation on Postoperative Pain: A Randomized, Double-Blind, Sham-Controlled Trial With Preoperative and Postoperative Sessions

What this Trial Is About

Researchers are evaluating whether different frequencies of transauricular vagus nerve stimulation (tVNS) can reduce postoperative pain and opioid use in adults undergoing abdominal or urologic surgery. This study also aims to assess how tVNS affects recovery quality, autonomic nervous system function, and treatment safety. The trial compares high-frequency tVNS, low-frequency tVNS, and sham stimulation to understand their different impacts on pain and autonomic responses after surgery. Participants are randomly assigned to receive either high-frequency tVNS (60-120 Hz), low-frequency tVNS (10-20 Hz), or sham stimulation, delivered bilaterally to the ear's vagus nerve branch. Each participant undergoes two 30-minute stimulation sessions: one before anesthesia and one after surgery in the post-anesthesia care unit. The stimulation current is adjusted between 2 and 6 mA based on comfort. Sham stimulation mimics active treatment without delivering electrical pulses. During the study, participants will be assessed for postoperative pain intensity, opioid consumption, need for additional pain medications, nausea, vomiting, heart rate changes, and overall recovery quality. Researchers will monitor for any adverse events related to the stimulation from the first session until 24 hours after surgery. The primary outcome is total opioid use in the first 24 hours post-surgery. The study will enroll 174 adults aged 18 to 59 years and lasts through 24 hours after surgery for outcome measurement.

Transauricular Vagus Nerve Stimulation Frequencies for Postoperative Pain