ED

Background: Children's minds are immature, making them more susceptible to severe anxiety when separated from their parents before surgery. Alleviating preoperative anxiety in children is essential for providing comfort-oriented healthcare. Remimazolam is a novel ultra-short-acting benzodiazepine. Existing studies have identified the effective dose for 50% of patients (ED Methods: From April to August 2025, pediatric patients undergoing elective surgery under general anesthesia were enrolled and stratified into two age groups: a younger group (YG, aged 1 to <4 years) and an older group (OG, aged 4-6 years inclusive). We employed the biased coin design (BCD) to determine target doses, defining a positive response as effective relief of preoperative anxiety [Parent Separation Anxiety Scale (PSAS) score < 3]. The initial dose for the first patient was 0.2 mg/kg. For subsequent pediatric patients, the dose was adjusted by increasing or decreasing by 0.05 mg/kg based on sedation response of the previous case. Isotonic regression and bootstrapping methods were used to estimate the ED Results: Eighty children completed the study, 40 in YG group and 40 in OG group. Statistical analysis indicated that the ED Conclusion: The ED Clinical Trial Registration: https://www.chictr.org.cn/bin/project/edit?pid=252632, identifier ChiCTR2500098747.