The optimal clinical dose of alfentanil for tracheal intubation during inhalation induction with sevoflurane after sedation with ketamine in children

ABSTRACT

BACKGROUND: The purpose of this study was to determine the clinical effective dose of alfentanil required for successful tracheal intubation during inhalation induction using 5% sevoflurane without neuromuscular blockade in children sedated with ketamine. METHODS: Twenty-one children, aged 3-10 years, undergoing surgeries under general anesthesia were enrolled into the study. All patients were premedicated with 0.004 mg/kg glycopyrrolate intramuscularly 30 min before anesthesia.To facilitate separation of the child from the parents, intravenous 1 mg/kg ketamine was given prior to transfer into the operating room.After inhalation induction with 5% sevoflurane and 100% oxygen, pre-determined dose of alfentanil was injected over 20 sec. The dose of alfentanil was determined by modified Dixon's up-and-down method (2microgramkg as a step size starting from 12microgramkg).The study ended when six independent pairs of patients, who manifested cross over from 'failure' to 'success' for tracheal intubation, were recruited. RESULTS: In 50% of children, the effective bolus dose (ED50) (95% confidence intervals) of alfentanil for successful tracheal intubation was 7.2microgram/kg (6.3-8.1microgram/kg) during sevoflurane inhalation induction.From isotonic regression, 95% effective dose (ED95) (95% confidence intervals) of alfentanil was 9.9microgram/kg (2.2-16.0microgram/kg). CONCLUSIONS: During inhalation induction using 5% sevoflurane without neuromuscular blockade after ketamine sedation, the ED50 and ED95 of alfentanil for successful tracheal intubation were 7.2 microgram/kg and 9.9microgram/kg in children, respectively.