Optimum time for intravenous cannulation after induction with sevoflurane, oxygen, and nitrous oxide in children without any premedication

Background: Intravenous cannulation is usually done in children after inhalational induction with volatile anesthetic agents. The optimum time for safe intravenous cannulation after induction with sevoflurane, oxygen, and nitrous oxide has been studied in premedicated children, but there is no information for the optimum time for cannulation with inhalational induction in children without premedication. Aims: The aim of this study was to determine the optimum time for intravenous cannulation after the induction of anesthesia with sevoflurane, oxygen, and nitrous oxide in children without any premedication. Methods: This is a prospective, observer-blinded, up-and-down sequential allocation study in unpremedicated ASA grade 1 children aged 2-6years undergoing elective dental surgery. Intravenous cannulation was attempted after inhalational induction with sevoflurane, oxygen, and nitrous oxide. The timing of cannulation was considered adequate if there was no movement, coughing, or laryngospasm. The cannulation attempt for the first child was set at 4minutes after the loss of eyelash reflex and the time for intravenous cannulation was determined by the up-and-down method using 15seconds as step size. Probit test was used to analyze the up-down sequences for the study. Results: The adequate time for effective cannulation after induction with sevoflurane, oxygen, and nitrous oxide in 50% and 95% of patients was 53.02seconds (95% confidence limits, 20.23-67.76seconds) and 87.21seconds (95% confidence limits, 70.77-248.03seconds), respectively. Conclusion: We recommend waiting for 1minute 45seconds (105seconds) after the loss of eyelash reflex before attempting intravenous cannulation in pediatric patients induced with sevoflurane, oxygen, and nitrous oxide without any premedication.