TEAS for Sedation During ERCP: A Multicenter Trial With Mechanistic Substudy

1. The goal of this clinical trial is to learn if transcutaneous electrical acupoint stimulation (TEAS), a non-invasive therapy that applies mild electrical current to specific points on the skin, can help patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) better tolerate the procedure and experience fewer complications related to sedation. It will also explore the underlying neuro-endocrine-immune mechanisms by measuring changes in serum biomarkers. 2. The main questions the study aims to answer are: (1)Does TEAS reduce the incidence of sedation-related adverse events (such as low blood oxygen, low blood pressure, or breathing problems) during ERCP? (2)Does TEAS improve patient comfort and reduce the need for additional sedative medications during the procedure? (3)Does TEAS lead to faster recovery and higher patient and physician satisfaction? (4) Does TEAS modulate the neuro-endocrine-immune network, as reflected by changes in serum β-endorphin, cortisol, TNF-α, and IL-6 levels? 3.Researchers will compare two approaches: 1. Active TEAS: Electrical stimulation at specific points on the legs and arms before and during ERCP. 2. Sham TEAS: Pads placed on the same points but no electrical stimulation delivered (the device appears active). 4.All participants will receive standard conscious sedation with meperidine and diazepam, which is commonly used for ERCP in many centers. Participants will be randomly assigned to one of the two groups. The study will measure sedation-related complications, pain levels, medication requirements, recovery times, satisfaction scores, and changes in serum biomarkers (β-endorphin, cortisol, TNF-α, IL-6).

1\. Inclusion Criteria: 1. Patients aged 18-85 years scheduled for elective diagnostic or therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for pancreaticobiliary indications. 2. American Society of Anesthesiologists (ASA) physical status classification I, II, or III. 3. Body mass index (BMI) between 18 and 30 kg/m². 4. Willing and able to provide written informed consent. 2\. Exclusion Criteria: 1. Known allergy or contraindication to meperidine, diazepam, or any other medication used in the protocol. 2. Chronic use of benzodiazepines or opioids (regular use more than three times per week in the preceding three months). 3. Severe cardiopulmonary, hepatic, or renal dysfunction (e.g., New York Heart Association class III or IV heart failure, uncontrolled chronic obstructive pulmonary disease, estimated glomerular filtration rate \