Table 1_ED90 of intravenous remimazolam for alleviating preoperative anxiety in children: a prospective dose-finding study.doc

BackgroundChildren’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 (ED50) when administering intravenous remimazolam to alleviate preoperative anxiety in children. However, the 90% effective dose (ED90) is clinically more meaningful. This study aims to determine the ED90 of intravenous remimazolam in alleviating preoperative anxiety in pediatric patients aged 1–6 years.
MethodsFrom 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 ED90 and 90% confidence interval (CI), respectively.
ResultsEighty children completed the study, 40 in YG group and 40 in OG group. Statistical analysis indicated that the ED90 (90% CIs) values for remimazolam used for alleviating preoperative anxiety in pediatric patients were 0.20 mg/kg (0.17–0.24) in the YG group and 0.15 mg/kg (0.11–0.17) in the OG group. Given that the 83% CIs for the ED90 showed no overlap between the YG group (0.18–0.24) and the OG group (0.12–0.17), the difference between the two groups is considered statistically significant.
ConclusionThe ED90 of intravenous remimazolam for preoperative anxiolysis was 0.20 mg/kg in children aged 1 to <4 years and 0.15 mg/kg in those aged 4–6 years. Notably, older children require even lower weight-based doses.
Clinical Trial Registrationhttps://www.chictr.org.cn/bin/project/edit?pid=252632, identifier ChiCTR2500098747.