An optimum time for intravenous cannulation after induction with sevoflurane in children

Background: It is a common practice to perform inhalational induction with sevoflurane followed by intravenous cannulation in children. However, there is little information regarding the time at which the intravenous cannulation can be attempted safely after sevoflurane induction. Methods: Pediatric patients aged 4-10 years receiving sevoflurane inhalational induction for elective cases were recruited. General anesthesia was induced with sevoflurane and oxygen via mask, then intravenous cannulation was attempted. The time for intravenous cannulation was determined by the use of up-and-down method using 30 s as a step size. Intravenous cannulation without any movement, coughing, or laryngospasm was considered successful. The up-and-down sequences were analyzed by the probit test. Results: The time for effective intravenous cannulation in 50% patients was 1.90 min (95% confidence limits, 1.24-2.41 min). The time for effective cannulation in 95% of patient population was 3.32 min (95% confidence limits, 2.68-6.77 min). Conclusion: We recommend an optimal time of 3.5 min for attempting intravenous cannulation after the loss of eyelash reflex with sevoflurane induction.