| Abstract
| - Background. We studied 63 ASA I children (age 2-8 yr) to determine the sufentanil dose needed to facilitate intubation under excellent conditions after inhalation induction with various end-tidal concentrations of sevoflurane without neuromuscular block. Methods. Subjects were allocated randomly to receive sevoflurane end-tidal concentrations (e′sevo) of 2.5%, 3%, or 3.5%. Anaesthesia was induced with sevoflurane 6% without nitrous oxide for 2 min, and then inspired sevoflurane concentration was adjusted to keep e′sevo at 2.5%, 3%, or 3.5% according to the group. Subjects received i.v. sufentanil according to an ‘up and down’ design. Tracheal intubation by direct laryngoscopy was performed 6 min after sufentanil injection. Intubation was considered successful, if intubation conditions were excellent as determined by the laryngoscopist. Results. The ED50 [effective dose for 50% of subjects; mean (sd)] of sufentanil required for excellent intubation conditions was 0.6 (0.12), 0.32 (0.10), or 0.11 (0.07) µg kg−1 for e′sevo of 2.5%, 3%, or 3.5%, respectively. Using logistic analysis, the 95% effective dose (ED95) of sufentanil was 1.02 [95% confidence intervals (CI) 0.31-1.74] µg kg−1, 0.58 (95% CI 0.17-0.99) µg kg−1, or 0.28 (95% CI 0.04-0.52) µg kg−1 for e′sevo of 2.5%, 3%, or 3.5%, respectively. Conclusions. Excellent intubation conditions could be obtained in children after inhalation induction with low sevoflurane concentrations and adjuvant sufentanil.
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