Transcutaneous Auricular Vagus Nerve Stimulation: Participants in this arm receive active transcutaneous auricular vagus nerve stimulation (ta-VNS) using the tVNS501 device. Stimulation is delivered to the left cymba conchae (auricular branch of the vagus nerve) with the following parameters: frequency 25 Hz, pulse width 250 µs, 30 seconds on / 30 seconds off cycling. Intensity is adjusted starting from 0.4 V and increased in 0.4 V increments until the participant perceives mild discomfort, then reduced to the highest tolerable non-painful level. The intervention begins on the day of surgery (from the preoperative holding area through 6 hours postoperatively in the ICU) and continues on postoperative days 1 through 5 with two 120-minute sessions per day (at 9:00 and 14:00). The device is applied by trained non-blinded operators.
Sham Stimulation: Participants in this arm receive sham stimulation using the same tVNS501 device. Electrodes are placed on the left cymba conchae following the same procedure as the active group, but no electrical current is delivered. The stimulation settings are displayed on the device to maintain blinding, but the output is turned off. The schedule and duration of device application are identical to those in the active stimulation group.
Study summary
Acute kidney injury (AKI) is a common complication after cardiac surgery using cardiopulmonary bypass, leading to longer hospital stays and worse outcomes. Effective preventive therapies are lacking.
This randomized controlled trial investigates whether transcutaneous auricular vagus nerve stimulation (taVNS)-a non-invasive ear stimulation technique-can reduce AKI after cardiac surgery. A total of 152 patients undergoing elective cardiac surgery with cardiopulmonary bypass will be randomly assigned to receive either taVNS or sham stimulation. The intervention begins before surgery and continues daily through postoperative day 5.
The primary outcome is the incidence of AKI within 7 days after surgery. Secondary outcomes include AKI severity, need for dialysis, kidney function recovery, complications, and inflammatory biomarkers.
This study is approved by the institutional ethics committee. All participants will provide written informed consent.
Eligibility
Sex
ALL
Min age
18 Years
Max age
—
Healthy volunteers
No
Inclusion Criteria:
* Age ≥18 years
* Scheduled for elective cardiac surgery with cardiopulmonary bypass under general anesthesia
* Baseline estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m² (CKD-EPI formula)
* American Society of Anesthesiologists (ASA) physical status classification I-III
* New York Heart Association (NYHA) functional classification I-III
* Able to understand and cooperate with study procedures
* Willing to participate and provide written informed consent. For participants unable to read or sign due to incapacity or illiteracy, consent may be obtained from a legally authorized representative or witnessed by an impartial third party as per ethical guidelines
Exclusion Criteria:
* Solitary kidney, history of kidney transplantation, pre-existing renal replacement therapy, or pre-existing acute kidney injury (KDIGO criteria)
* Contraindications to transcutaneous auricular vagus nerve stimulation, including active infection, dermatitis, skin breakdown, or severe psoriasis in the bilateral auricular region; allergy to silicone, electrode gel, or device materials; uncontrolled arrhythmia, symptomatic bradycardia, sick sinus syndrome, second- or third-degree atrioventricular block, implanted pacemaker or defibrillator; carotid sinus hypersensitivity; uncontrolled epilepsy; or active peptic ulcer disease
* Received vagus nerve stimulation, auricular acupuncture, or transcutaneous electrical nerve stimulation within 1 month prior to enrollment
* Long-term use of medications that significantly affect autonomic nervous system tone or renal blood flow and cannot be safely paused before surgery
* Active systemic infection or sepsis (Sepsis-3 criteria) prior to surgery
* Acute ischemic or hemorrhagic stroke, or acute myocardial infarction within 3 months prior to enrollment
* Severe hepatic dysfunction (Child-Pugh Class C), acute liver failure, or other serious life-threatening conditions
* Vulnerable populations (excluding elderly or illiterate individuals) including critically ill patients, individuals with psychiatric disorders, cognitive impairment, or pregnant women
* Any other condition deemed by the investigator to make the participant unsuitable for study participation
Primary outcome measure(s)
Incidence of Acute Kidney Injury (AKI) Within 7 Days After Surgery — Within 7 days after surgery
Trial sites (1)
Facility
City
Region
Status
Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
We use cookies to analyse site traffic and improve your experience. With your consent, we may also use cookies for advertising. You can change your choice at any time on our Cookie Policy page. See also our Privacy Policy.