Median effective dose (ED₅₀) of esketamine combined with propofol for children to inhibit response of gastroscope insertion

Propofol is the most commonly used drug for procedural sedation during gastroscopy. However, independent use of propofol can lead to increased dosage and additional side effects. Esketamine was found to be exceptional in combination with propofol for painless gastroscopy. No studies have calculated the median effective dose (ED₅₀) of esketamine combined with propofol in pediatric painless gastroscopy. Here, we designed a research to study the ED₅₀ of esketamine combined with propofol using the Dixon and Massey up-and-down sequential method for inhibiting the response of gastroscope insertion.

Children who met the inclusion and exclusion criteria were included in this study. Propofol and esketamine were used as anesthetics for painless gastroscopy in children. To explore the ED₅₀, the initial propofol dose was set at 3 mg/kg in all children. The first child was given an esketamine dose of 0.1 mg/kg, followed by 30 s of slow bolus injection propofol. If anesthesia induction failed (coughing or body movement of children during gastroscope insertion), the esketamine dose was elevated in the next child, with a interval difference of 0.05 mg/kg. Otherwise, if the anesthesia induction was successful, the next dosage was reduced by 0.05 mg/kg. The study was stopped if nine crossover inflection points were reached. The ED₅₀ of esketamine was calculated using probit regression, and the blood pressure, pulse oxygen saturation, heart rate, recovery time, and side effects were recorded in all children.

A total of 26 children were included in this study. The ED₅₀ of esketamine combined with 3 mg/kg propofol was 0.143 mg/kg (95% CI 0.047–0.398 mg/kg). The total consumption of propofol was 16.04 ± 5.37 mg. The recovery time was 16.38 ± 8.70 min. Adverse effects recorded were delayed awakening in two cases and increased oral secretions of another child during the examination inducing cough and hypoxemia (86% was the lowest).

The ED₅₀ of esketamine was 0.143 mg/kg when combined with 3 mg/kg propofol for successful sedation in pediatric gastroscope insertion. This sub-anaesthetic dose of esketamine was safe and efficacious with few complications in pediatric painless gastroscopy.

The study was registered at the Chinese Clinical Trial Registry (www.​chictr.​org.​cn; registration number: ChiCTR2100052830 on 06/11/2021).