Effective dose of propofol combined with intravenous esketamine for smooth flexible laryngeal mask airway insertion in two distinct age groups of preschool children.

Background: There is limited research on the combined use of propofol and esketamine for anesthesia induction during flexible laryngeal mask airway (FLMA) in pediatric patients, and the effective dosage of propofol for FLMA smooth insertion remains unclear. We explored the effective dose of propofol combined with intravenous esketamine for the smooth insertion of FLMA in two distinct age groups of preschool children. Methods: This is a prospective, observer-blind, interventional clinical study. Based on age, preschool children scheduled for elective surgery were divided into group A (aged 1–3 years) and group B (aged 3–6 years). Anesthesia induction was started with intravenous administration of esketamine (1.0 mg.kg− 1) followed by propofol administration. The FLMA was inserted 2 min after propofol administration at the target dose. The initial dose of propofol in group A and group B was 3.0 mg.kg− 1 and 2.5 mg.kg− 1, respectively. The target dose of propofol was determined with Dixon's up-and-down method, and the dosing interval of propofol was 0.5 mg.kg− 1. If there was smooth insertion of FLMA in the previous patient, the target dose of propofol for the next patient was reduced by 0.5 mg.kg− 1; otherwise, it was increased by 0.5 mg.kg− 1. The median 50% effective dose (ED50) for propofol was estimated using Dixon's up-and-down method and Probit analysis, while the 95% effective dose (ED95) was estimated through Probit analysis. Vital signs and adverse events during induction were recorded. Results: Each group included 24 pediatric patients. Using Dixon's up-and-down method, the ED50 of propofol combined with esketamine for smooth insertion of FLMA in group A was 2.67 mg.kg− 1 (95%CI: 1.63–3.72), which was higher than that in group B (2.10 mg. kg− 1, 95%CI: 1.36–2.84) (p = 0.04). Using Probit analysis, the ED50 of propofol was calculated as 2.44 (95% CI: 1.02–3.15) mg.kg− 1 in group A and 1.93 (95% CI: 1.39–2.32) mg.kg− 1 in group B. The ED95 of propofol was 3.72 (95%CI: 3.07–15.18) mg.kg− 1 in group A and 2.74 (95%CI: 2.34–5.54) mg.kg− 1 in group B. In Group B, one pediatric patient experienced laryngospasm. Conclusion: The effective dose of propofol when combined with intravenous esketamine for smooth insertion of FLMA in children aged 1–3 years is 2.67 mg.kg− 1, which is higher than that in children aged 3–6 years (2.10 mg. kg− 1). Trial registration: Chinese Clinical Trial Registry Center (Registration Number: ChiCTR2100044317; Registration Date: 2021/03/16) [ABSTRACT FROM AUTHOR]