The 90% effective dose of remimazolam in combination with sufentanil for sedation in patients undergoing gastroscopy

Objective To determine the 90% effective dose (ED 90 ) of remimazolam in combination with sufentanil for sedation in patients undergoing gastroscopy. Methods Fifty-six patients aged 18–65 years with ASA physical status I–II and a BMI of 18–30 kg/m 2 who were scheduled for gastroscopy were enrolled. All patients received 5 μg of sufentanil, followed 3 min later by an initial dose of 5 mg remimazolam. The dose was determined using a two-stage biased-coin design up-and-down sequential method, with each patient's dose based on the response of the preceding patient. Dose adjustments were made in 2.5 mg increments. For failure of sedation (negative response: coughing, body movement, or MOAA/S > 1 during pharyngeal passage), the dose for the next patient was increased deterministically by 2.5 mg; for success of sedation (positive response: MOAA/S ≤ 1), the dose was decreased with 11% probability or kept unchanged with 89% probability. ED 90 and its 95% confidence interval (CI) were estimated using isotonic regression with bootstrap resampling. The incidence of adverse events during sedation was recorded. Results The ED 90 of remimazolam combined with 5 μg of sufentanil was 17.625 mg (95% CI: 15.467–20.000 mg). Six patients experienced coughing, and seven developed transient hypotension during sedation. No other adverse events were observed. Conclusion The ED 90 of remimazolam combined with sufentanil for gastroscopy sedation was 17.625 mg, with a low incidence of adverse events. These results provided a clinically relevant dosing benchmark for this promising drug combination.