Low doses of rocuronium during remifentanil-propofol-based anesthesia in children: comparison of intubating conditions

BACKGROUND : In this prospective double-blind study, intubation conditions were compared at 90 s following two different low doses of rocuronium during remifentanil and propofol anesthesia in children undergoing ambulatory procedures. METHODS : Forty-four children (ASA I-II, aged 3-12 years) undergoing day case ENT surgery were premedicated with midazolam 0.5 mg x kg(-1). Following atropine 10 microg x kg(-1), remifentanil infusion 0.5 microg x kg(-1) x min(-1) was started. After 60 s, anesthesia was induced with propofol 2.5 mg x kg(-1). Immediately after a bolus dose of propofol, the children received rocuronium doses of 0.15 mg x kg(-1) (group I, n = 22) or 0.3 mg x kg(-1) (group II, n = 22) in a randomized manner, after which an infusion of propofol 6 mg x kg(-1) h(-1) was added to the infusion of remifentanil 0.5 microg x kg(-1) min(-1) for maintenance of anesthesia. Intubating conditions were evaluated 90 s after rocuronium administration applying the Copenhagen Scoring System which included components of laryngoscopy, vocal cord movement and reaction to intubation. Hemodynamic values were recorded at predetermined time intervals. RESULTS : Excellent, good and poor intubation conditions were 18.2, 40.9 and 40.9% in group I and 40.9, 54.5 and 4.5% in group II. Clinically acceptable intubating conditions (excellent and good) were significantly higher in group II (95.5%) than in group I (59.1%) (P = 0.004). Mean values of heart rate and blood pressure did not differ significantly between groups. No children required any intervention for hemodynamic instability and/or muscle rigidity. CONCLUSIONS : The results suggest that 0.3 mg x kg(-1) of rocuronium may be a better low dose than 0.15 mg x kg(-1) of rocuronium for clinically acceptable intubating conditions in pediatric ambulatory surgery during remifentanil-propofol-based anesthesia at the doses used in the study.