Remimazolam besylate reduces hypoxemia during painless gastrointestinal endoscopy in elderly patients: study protocol for a multicenter, randomized, controlled trial

BACKGROUND: Hypoxemia and circulatory depression are common complications in elderly patients undergoing procedure sedation anesthesia (PSA) for gastrointestinal (GI) endoscopy. Remimazolam besylate, a novel ultra-short-acting benzodiazepine, is postulated to offer a superior safety profile with reduced respiratory depressant effects compared to propofol. This study aims to compare the incidence of hypoxemia of remimazolam besylate versus propofol for painless GI endoscopy in elderly patients through a multicenter randomized controlled trial. METHODS: This study is a multicenter, double-blind, parallel, randomized, controlled trial. Six hundred seventy elderly patients scheduled for GI endoscopy under PSA are enrolled at three medical institutions in China from 2025 to 2027. Patients will be randomized 1:1 to receive remimazolam besylate (0.15 mg/kg) plus sufentanil vs propofol (1.5 mg/kg) plus sufentanil, stratified by age (65-70 vs.70-75 years old) and 3 research institution. The primary outcome is the incidence of intraoperative hypoxemia, defined as any event where peripheral oxygen saturation (SpO₂) is ≥ 75% and < 90%, lasting for less than 60 s. Secondary outcomes include hypoxemia degree, emergency airway management, propofol consumption, hemodynamic stability, involuntary body movements, procedure/recovery times, and clinician satisfaction. DISCUSSION: This trial evaluates whether remimazolam besylate reduces respiratory depression and improves safety profiles in elderly patients during painless GI endoscopy. It may provide evidence for optimizing sedation strategies in high-risk elderly populations. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2500110081, registrated on September 30, 2025.