An interventional study of Transcutaneous Auricular Vagus Nerve Stimulator in Hypoxemia, sponsored by Affiliated Hospital of Nantong University. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-18.
Sponsored by Affiliated Hospital of Nantong University · Not applicable, Interventional, and Prevention
Hypoxemia is a common complication in the post-anesthesia care unit (PACU) and represents one of the most meaningful factors associated with poor patient prognosis. Obese patients have a relatively higher incidence of hypoxemia. This may be partly attributable to their unique physiological characteristics. In addition, surgical trauma triggers a systemic inflammatory response with the release of pro-inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). These mediators increase pulmonary capillary permeability, induce pulmonary edema, and further impair gas exchange. Surgically-induced stress elevates sympathetic tone and reduces vagal activity, which alters bronchial tone and respiratory rhythm and consequently compromises pulmonary function.Postoperative hypoxemia not only prolongs recovery time and increases the likelihood of ICU admission, but severe episodes may also lead to arrhythmia, myocardial ischemia, long-term cognitive and psychiatric disorders, and even cardiac arrest and death. These outcomes impair postoperative recovery and long-term prognosis, prolong hospital stay, and raise healthcare costs.
Although strategies such as postoperative semi-recumbent positioning and intraoperative protective ventilation have been explored, there are currently no preferred interventions or clear clinical guidelines for the prevention of postoperative hypoxemia.
As a non-invasive technique, transcutaneous auricular vagus nerve stimulation (taVNS) activates the auricular branch of the vagus nerve by stimulating the cymba conchae. Vagal activation suppresses macrophage activity and reduces the release of pro-inflammatory cytokines including TNF-α, IL-1β, IL-6 and IL-18, thereby attenuating pulmonary inflammation and edema and improving oxygenation. Afferent vagal signals project to the nucleus tractus solitarius, modulating the medullary respiratory center, respiratory rate and ventilation efficiency. taVNS is easy to perform, safe, applicable in the perioperative period, and has shown promising effects in regulating inflammatory conditions.
This study aims to investigate whether perioperative taVNS reduces the incidence of hypoxemia in the PACU by attenuating excessive sympathetic activation and mitigating pulmonary and systemic inflammatory responses.
1,076 studies on the registry are indexed under Hypoxia; 213 are open to participants now.
This study's planned enrollment of 80 is above the median of 45 across 769 interventional studies indexed under Hypoxia.
Browse Hypoxia studies →Affiliated Hospital of Nantong University is the lead sponsor of 97 studies on the registry; 57 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Age ≥18 years; Scheduled for elective bariatric surgery; Classified as (ASA) physical status I to III; Capable of understanding the study procedures and various assessment scales and able to effectively communicate with the researchers; Willing to participate in the study and provide written .
Exclusion Criteria:
Patients with severe underlying cardiopulmonary diseases (e.g., acute exacerbation of , acute myocardial infarction, class Ⅳ heart failure); Patients with resting SpO₂ \<90% before surgery; Patients with a preoperative heart rate below 50 beats per minute or severe arrhythmia; Patients with lesions of the auricular concha (e.g., inflammation, ulcer, deformity, implant) or vagus nerve dysfunction (e.g., diabetic peripheral neuropathy, vagus nerve injury due to prior neck surgery); Patients with a history of implanted stimulators (e.g., pacemakers, implanted vagus nerve stimulators, deep brain stimulators, spinal cord stimulators), cochlear implants, or metallic implants (excluding dental work); Patients with cognitive dysfunction ( score \<20), psychiatric disorders, or unable to cooperate with study procedures; Patients who received vagus nerve stimulation or acupuncture within 1 month before the study; Patients with skin damage or dermatological conditions at the electrical stimulation site; Pregnant or lactating women; Patients requiring emergency surgery; Patients participating in other clinical trials.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
MMSE and MoCA
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients in the taVNS group will have a transcutaneous auricular vagus nerve stimulation device with a transparent, non-insulated thin film placed on the cymba conchae of the left ear. TaVNS will be administered on the day of surgery (starting 30 minutes before anesthesia induction and continuing until the end of the surgery, terminating after the removal of the endotracheal tube in the PACU). The stimulation parameters are set as follows: frequency 20 Hz, pulse width 200 μs, 30 seconds on / 30 seconds off, with the current intensity set to the maximum amplitude the patient can tolerate (just below the pain threshold).
Device: Transcutaneous Auricular Vagus Nerve Stimulator
Patients in the Sham taVNS group will have a transcutaneous auricular vagus nerve stimulation device with a transparent insulating film placed on the cymba conchae of the left ear on the day of surgery. The stimulation parameters, method, and duration will be the same as those in the taVNS group. However, due to the insulating film applied to the stimulation device in the sham group, patients will not actually receive any stimulation.
Intervention Timing of Transcutaneous Auricular Vagus Nerve Stimulator: The intervention will begin 30 minutes before anesthesia induction and continue until the end of the surgery, terminating after the removal of the endotracheal tube in the PACU. The stimulation parameters are set as follows: frequency 20 Hz, pulse width 200 μs, 30 seconds on / 30 seconds off, with the current intensity set to the maximum amplitude the patient can tolerate (just below the pain threshold).
Incidence of Postoperative Hypoxemia in the PACU
Numerous clinical studies and consensus statements define hypoxemia as either peripheral oxygen saturation (SpO₂) less than 90% lasting for more than 10 seconds, or a partial pressure of arterial oxygen to fraction of inspired oxygen (PaO₂/FiO₂) ratio less than 300 mmHg during PACU stay.
Time frame: Within 30 minutes in the PACU postoperatively
Incidence and First Onset Time of Moderate Hypoxemia in the PACU
Moderate hypoxemia is defined as SpO₂ less than 85% lasting for more than 10 seconds during PACU stay.The first onset time was defined as the time interval from extubation to the first onset of severe hypoxemia.
Time frame: Within 30 minutes in the PACU postoperatively
Incidence of Airway Rescue
Airway rescue was defined as the implementation of non-invasive mask ventilation or re-intubation for respiratory support.
Time frame: Within 30 minutes in the PACU postoperatively
Time to Extubation and PACU Length of Stay
The time interval from the end of surgical procedure to tracheal extubation. The time interval from PACU admission to PACU discharge.
Time frame: Within 30 minutes in the PACU postoperatively
Postoperative Respiratory Comfort Score
Respiratory comfort was evaluated using a 0-10 numerical rating scale, with higher scores indicating better respiratory comfort and lower scores indicating more severe respiratory discomfort.
Time frame: Within 30 minutes in the PACU postoperatively
Incidence of Cough, Pulmonary Infection and Atelectasis within 24 hours after surgery
Time frame: Within the first day post-surgery
Postoperative Visual Analogue Scale (VAS) pain score
VAS scores were assessed at two states: resting state and coughing state, with scores ranging from 0 to 10 points.
Time frame: Within the first day post-surgery
Total Length of Hospital Stay
The total length of hospital stay refers to the entire duration of the hospitalization from admission to diacharge
Time frame: Up to 5 weeks postoperatively
Incidence and Severity of Related Adverse Reactions
Adverse reactions included ear skin erythema, local pain, dizziness, nausea, and bradycardia (heart rate \< 50 beats per minute). The severity of adverse reactions was graded according to the following standards: Grade 1, mild discomfort without the need for clinical intervention; Grade 2, symptoms relieved after symptomatic treatment; Grade 3, severe adverse reactions requiring termination of study intervention and formal clinical treatment.
Time frame: Up to 5 weeks postoperatively
No study locations are listed for this record.
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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Affiliated Hospital of Nantong University