Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Postoperative Opioid Consumption in Patients Undergoing Major Abdominal Surgery

This study aims to design a prospective, double-blind, randomized controlled trial to compare the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on postoperative visceral pain in patients undergoing major abdominal surgery. Participants will be randomly assigned to receive either taVNS or sham stimulation. The total consumption of opioids and other analgesics within 24 hours post-surgery in the AICU will be recorded, along with follow-up assessments of pain scores and quality of recovery scores (Qor-15) at 24 hours postoperatively.

Study Overview

• Status: Not yet recruiting
• Conditions: Pain Management
• Intervention / Treatment: Device: Transcutaneous auricular vagus nerve stimulation; Device: Sham Transcutaneous auricular vagus nerve stimulation

• Study Type: Interventional
• Enrollment (Estimated): 108
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mingzi An; Phone Number: 18035193080; Email: anmingzizi@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age between 18 and 85 years, regardless of gender
• ASA physical status classification I-III
• Scheduled for elective major abdominal surgery under general anesthesia, with postoperative admission to the AICU for monitoring
• Anticipated duration of stay in the AICU is approximately 24 hours

Exclusion Criteria:

• History of vagus nerve-related diseases (such as vasovagal syncope);
• Severe arrhythmias or implanted electronic devices such as pacemakers;
• Skin lesions, infections, or deformities at the site of external ear stimulation;
• Long-term preoperative use of opioid medications or sedatives;
• Allergy to study-related medications;

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: transcutaneous vagus nerve stimulation(taVNS); Patients received taVNS treatment immediately upon entering the AICU, with sessions occurring every 2 hours. A specialized taVNS stimulator device was used, and the left ear was cleaned with an alcohol swab or wet tissue before inserting an earplug with electrode contacts into the left ear, ensuring a snug fit. A second earplug was inserted into the right ear. The stimulation parameters were set as follows: continuous wave, frequency 20 Hz, pulse width 200 μs. Each treatment session lasted for 30 minutes.	Device: Transcutaneous auricular vagus nerve stimulation; Patients received taVNS treatment immediately upon entering the AICU, with sessions occurring every 2 hours. A specialized taVNS stimulator device was used, and the left auricle was cleaned with an alcohol swab or wet tissue before inserting an earplug with electrode contacts into the left ear, ensuring a snug fit. A second earplug was inserted into the right ear. The stimulation parameters were set as follows: continuous wave, frequency of 20 Hz, and pulse width of 200 μs. Each treatment session lasted for 30 minutes.
Placebo Comparator: Sham-stimulation; The treatment protocol was identical to that of the taVNS group. Electrodes were placed on the left auricle. After the device was activated, it either did not deliver any current or only emitted a brief sub-threshold current to simulate the sensation of device activation, without producing continuous neural stimulation.	Device: Sham Transcutaneous auricular vagus nerve stimulation; The treatment protocol was identical to that of the taVNS group. Electrodes were placed on the left auricle. After the device was turned on, it either did not output any current or only delivered a brief sub-threshold current to simulate the sensation of the device being activated, without producing continuous neural stimulation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total consumption of opioids	Total consumption of opioids (morphine equivalent) within 24 hours postoperatively.	within 24 hours postoperatively.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adverse events associated with taVNS	Adverse events associated with taVNS (local skin irritation, dizziness, tinnitus, etc.);	24 Hours Postoperatively
The incidence of opioid-related complications	The incidence of opioid-related complications (such as respiratory depression, nausea and vomiting, and intestinal paralysis) within 24 hours post-surgery.	within 24 hours post-surgery
sleep quality score	Postoperative first-night sleep quality score (Richards-Campbell Sleep Questionnaire, RCSQ); the score ranges from 0 to 150, with higher scores indicating better sleep quality.	Postoperative first-night
Quality of Recovery Score	Quality of Recovery Score (QoR-15) at 24 Hours Post-Operatively;The score ranges from 0 to 150 points, with higher scores indicating better postoperative recovery quality.	24 Hours Post-Operatively

Collaborators and Investigators

• Sponsor: Affiliated Hospital of Jiaxing University

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2026
• Primary Completion (Estimated): December 30, 2027
• Study Completion (Estimated): December 30, 2027

Study Registration Dates

• First Submitted: November 22, 2025
• First Submitted That Met QC Criteria: November 22, 2025
• First Posted (Estimated): December 3, 2025

Study Record Updates

• Last Update Posted (Actual): December 16, 2025
• Last Update Submitted That Met QC Criteria: December 8, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Neurobehavioral Manifestations; Perceptual Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Agnosia
• Other Study ID Numbers: 2025-LP-778

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No