Sample size estimation
In our routine practice, the success rate of procedure sedation was about 40% in young patients and 50% in elderly patients when used sufentanil only. Based on preliminary observation, additional use of 0.06 mg/kg remimazolam in 20 young patients and 0.04 mg/kg in 20 elder patients increased the success rate to 75 and 80%, respectively. Assumed the significance level at 0.05, power at 0.8, and a drop-out rate of 5%, the sample size required to detect difference was 90 in the young patients and 114 in the elderly patients. Sample size calculation was performed with the PASS software (version 15.0, NCSS PASS, Utah, USA).