Dose requirements of remifentanil for intubation in nonparalyzed Chinese children

Background The objective of this study was to determine ED50 and ED95 of remifentanil for intubation combined with propofol in nonparalyzed Chinese children. Methods Forty-seven American Society of Anesthesiologists Class I children aged 4-11 years weighing 14-33.5 kg underwent general anesthesia with 2.5 mg·kg^-1 of intravenous propofol followed by remifentanil in Wenzhou, China. The initial dose of remifentanil was 2.5 μg·kg ^-1 injected over 60 s. Intubation was attempted 30 s after the completion of remifentanil injection. Level of difficulty to intubate was graded on a scoring system. If the initial intubation condition was deemed satisfactory, subsequent remifentanil doses were decreased by 0.25 μg·kg^-1. If the intubating condition was deemed unsatisfactory, subsequent remifentanil doses were increased by 0.25 μg·kg^-1. Mean arterial pressure, heart rate, and pulse oximetry were documented before and after induction, immediately after intubation, and 1 min after intubation. Results The ED50 of remifentanil used to render a satisfactory intubating condition used in combination with 2.5 mg·kg^-1 of propofol in nonparalyzed Chinese children was 2.30 μg·kg^-1 (95% confidence interval: 2.28-2.31 μg·kg^-1), and the ED95 is 2.75 μg·kg^-1 (95% confidence interval: 2.59-3.35 μg·kg^-1). These doses were lower than previously reported. Conclusion When used in combination with 2.5 mg·kg^-1 of intravenous propofol, ED50 and ED95 of remifentanil for adequate intubation in nonparalyzed children were lower than previously reported, at 2.30 and 2.75 μg·kg^-1, respectively.