Determining the 90% Effective Dose of Remimazolam Inhibiting Responses to Upper Gastrointestinal Endoscopy Insertion in Adults: A Double-Blind Study Utilizing a Biased Coin Up-and-Down Sequential Method

Background. Remimazolam, a benzodiazepine sedative with clinical advantages, is used for anesthesia during GI endoscopy. However, the accurate clinical dosage remains understudied. This study aims to investigate the 90% effective dose (ED90) of remimazolam in inhibiting responses to upper GI endoscopy insertion and evaluate its efficacy and safety for upper GI endoscopic diagnosis and treatment. Methods. A total of 54 adult patients undergoing upper GI endoscopy under procedural sedation were included, and they were anesthetized with an intravenous bolus of remimazolam. The first patient was given a dose of 0.3 mg/kg of remimazolam and was next randomized according to a biased coin design (BCD) method, and each patient received a dose of remimazolam depending on the response of the previous patient. A positive reaction was defined as no choking cough, nausea and vomiting, and/or motor response during placement of the upper GI endoscope into pharyngeal cavity or within 3 minutes after placement; otherwise, it was a negative reaction. If positive, randomize the next patient’s dose of remimazolam to be unchanged or decrease by 0.05 mg/kg. If negative, increase the next patient’s dose of remimazolam by 0.05 mg/kg. According to the study protocol, at least 45 patients with positive reactions were needed to suspend the trial while monitoring anesthesia-related adverse events. Results. The ED90 of remimazolam for upper gastrointestinal endoscopy insertion was 0.556 mg/kg (95% CI: 0.399–0.578). All patients maintained stable circulation and no serious adverse events were observed during sedation. Patient satisfaction was 4.89 ± 0.69 points, anesthesiologist satisfaction was 4.57 ± 0.96 points, and endoscopist satisfaction was 4.67 ± 0.87 points (full score 5 points, minimum 1 point). Conclusion. The use of remimazolam for upper gastrointestinal endoscopy was safe and effective, with a single intravenous bolus at an ED90 dose of 0.556 mg/kg inhibiting responses to the procedure.