Median effective dosage of midazolam oral solution for preschool children in preoperative sedation

This study aimed to detect median effective dosage (ED₅₀) of midazolam oral solution (MOS) for preschool children in preoperative sedation. Thirty children (3–6 years old, with a body mass index (BMI) of 18–28 kg/m², American Society of Anesthesiologists status (ASA) I-II) scheduled for the hidden penis correction surgery under general anesthesia were selected. The effective dosage of MOS for preschool children in preoperative sedation was measured by sequential method. The initial dose was set at 0.5 mg/kg, with a concentration gradient of 0.1 mg/kg. Sedation was deemed successful if the patients’ Ramsay sedation scores were ≥4 and Frankl treatment compliance rating scale was ≥3, without any grade III or higher adverse events during anesthesia. If these criteria were met, the dosage for the next patient was reduced by one gradient based on the last patient's dosage, otherwise, the dosage for the next patient was increased by one gradient. This process was repeated until the 7th inflection point from unsuccessful to successful sedation was reached, at which point the trial was terminated. Probit regression analysis was used to calculate the ED₅₀, 95% effective doses (ED₉₅) and 95% confidence interval (CI) of MOS. Adverse reactions such as bradycardia, nausea, vomiting, and blurred vision were recorded during sedation. This study revealed that the ED₅₀ and ED₉₅ of MOS for preschool children preoperative sedation are 0.627 mg/kg (95% CI 0.582–0.669 mg/kg) and 0.795 mg/kg (95% CI 0.712–1.211 mg/kg), respectively, providing a reference for the administration of MOS in this population.