Electroacupuncture at ST36 for Reducing Postoperative Inflammation After Cardiac Surgery With Cardiopulmonary Bypass

Effect of Electroacupuncture at Bilateral Zusanli (ST36) on Postoperative Inflammatory Response and Organ Injury in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass: A Prospective, Randomized, Parallel-Controlled Trial

Cardiac surgery using cardiopulmonary bypass can trigger a marked systemic inflammatory response and may contribute to postoperative organ dysfunction and delayed recovery. Electroacupuncture at the Zusanli acupoint (ST36) may regulate inflammatory responses, but its clinical effects in patients undergoing cardiac surgery remain uncertain.

This prospective, randomized, parallel-group study will enroll 140 adults undergoing elective cardiac surgery with cardiopulmonary bypass. After surgery and admission to the intensive care unit, participants will be randomly assigned in a 1:1 ratio to receive either bilateral ST36 electroacupuncture or a control procedure involving the same acupoint localization, skin disinfection, needle insertion, and needle retention without electrical stimulation. Both groups will receive standard postoperative care. The intervention will be administered twice for 30 minutes per session.

The primary outcomes are C-reactive protein levels and Sequential Organ Failure Assessment scores on postoperative day 2. Secondary outcomes include the duration of vasoactive drug use, incidence and severity of systemic inflammatory response syndrome, duration of mechanical ventilation, length of intensive care unit and hospital stay, and perioperative inflammatory markers. The study will evaluate whether ST36 electroacupuncture can reduce postoperative inflammation and organ injury and improve recovery after cardiac surgery.

Cardiopulmonary bypass, surgical trauma, and ischemia-reperfusion injury can induce a systemic inflammatory response after cardiac surgery. Excessive inflammation is associated with postoperative organ dysfunction and adverse clinical outcomes. Preclinical evidence suggests that electroacupuncture at ST36 may modulate systemic inflammation through neuroimmune pathways, including the vagal-adrenal axis. However, its clinical effectiveness in patients undergoing cardiac surgery with cardiopulmonary bypass has not been established.

Eligible participants will be randomized after returning to the intensive care unit following surgery. Participants in the experimental group will receive bilateral ST36 electroacupuncture in addition to standard postoperative treatment and nursing care. Electroacupuncture will be administered twice, with each session lasting 30 minutes. Participants in the control group will receive the same standard postoperative care and the same acupoint localization, skin disinfection, needle insertion, and needle retention procedures, but without electrical stimulation.

The primary outcomes are C-reactive protein levels and Sequential Organ Failure Assessment scores on postoperative day 2. Secondary assessments include vasoactive drug use, systemic inflammatory response syndrome, mechanical ventilation, intensive care unit and hospital length of stay, inflammatory cytokines, and other laboratory indicators of inflammation and organ function. The primary analysis will follow the intention-to-treat principle.

Inclusion Criteria:

• Age ≥18 years.
• Scheduled to undergo elective cardiac surgery with cardiopulmonary bypass (CPB) support.
• The surgical procedure may include coronary artery bypass grafting (CABG), valve replacement, valve repair, or another cardiac surgical procedure performed with CPB support.
• Voluntarily agrees to participate in the study and provides written informed consent. If a participant is unable to read and sign the informed consent form because of incapacity or another reason, the informed consent process will be conducted with the participant's legally authorized representative, who will sign on the participant's behalf. If a participant is unable to read the informed consent form, the informed consent process will be witnessed by an independent witness, who will sign the informed consent form.

Exclusion Criteria:

• Membership in a vulnerable population other than older adults or individuals who are illiterate, including patients with psychiatric disorders, cognitive impairment, critical illness, or another vulnerable condition.
• Pregnant or breastfeeding.
• Local skin or soft-tissue infection, erysipelas, or another condition at the acupuncture site that makes acupuncture treatment unsuitable.
• History of organ transplantation.
• Active malignancy.
• Long-term high-dose corticosteroid therapy before surgery, defined as prednisone ≥20 mg/day for ≥14 days or a cumulative prednisone-equivalent dose >700 mg.
• Severe chronic organ dysfunction before surgery, including any of the following:
• Chronic respiratory disease with a baseline PaO₂/FiO₂ ratio <300.
• Hematological disease, such as leukemia, lymphoma, or myeloma, or a baseline platelet count <100 × 10⁹/L.
• Chronic liver disease with total bilirubin >30 μmol/L.
• History of stroke or cerebral hemorrhage with a baseline Glasgow Coma Scale score <10.
• Chronic renal insufficiency with serum creatinine >110 μmol/L or long-term daily urine output <500 mL.
• Unable to tolerate electroacupuncture treatment.
• Currently participating in another interventional clinical study.
• Any other condition that, in the investigator's judgment, makes the patient unsuitable for participation.