Objective: We investigated the effects of two dexmedetomidine bolus and infusion combinations on the amount of sevoflurane required to produce 50% excellent tracheal intubation conditions (ED50 TI).
Methods: In a prospective, double-blinded parallel, randomized manner, 60 children (ASA I or II, age 3-8 years) undergoing elective surgery were allocated to one of three groups: saline only (group D0 ), a bolus dose of 1.0 μg·kg(-1) dexmedetomidine followed by a continuous infusion of 0.5 μg·kg(-1) ·h(-1) (group D1 ), or a bolus dose of 2.0 μg·kg(-1) dexmedetomidine followed by a continuous infusion of 1.0 μg·kg(-1) ·h(-1) (group D2 ). Each bolus dose of dexmedetomidine was infused over 10 min, after which a dexmedetomidine infusion and 5% sevoflurane were immediately begun, with sevoflurane subsequently adjusted to target specific values determined according to Dixon's up-and-down method. After the target concentration of sevoflurane was maintained stable for 15 min, laryngoscopy and tracheal intubation were performed. Intubation was considered excellent only if all subcomponents of the intubation score were rated excellent. Patient enrollment continued until there were six pairs of consecutive patients in which not excellent tracheal intubation conditions were followed by excellent conditions.
Results: The ED50 TI of sevoflurane in group D2 (1.41 ± 0.07%) was significantly lower than in group D1 (2.36 ± 0.16%; P < 0.001), the latter being significantly lower than in group D0 (3.52 ± 0.21%; P < 0.001).
Conclusion: Dexmedetomidine infusion produced a dose-dependent decrease in the ED50 TI of sevoflurane in children.
Keywords: ED 50; adrenergic alpha-Agonists; anesthesia; anesthetic; anesthetics volatile; dexmedetomidine; equipment; pediatric; sevoflurane; tracheal; tubes.
© 2014 John Wiley & Sons Ltd.