Effect of age on the median effective dose and 95% effective dose of intravenous fentanyl for blunting the hemodynamic response to tracheal intubation: A double-blind, up-and-down sequential method trial

Abstract

Control of the hemodynamic response during intubation is essential. To assess the effect of age on the median effective dose (ED50) and 95% effective dose (ED95) of fentanyl for blunting the hemodynamic response to intubation. Patients (n = 86) undergoing general anesthesia were randomly stratified according to age (groups 1–4); fentanyl was administered to each patient according to the Dixon and Massey method, starting at 2 μg/kg. The dose was increased or decreased by 0.5 μg/kg for the subsequent patient, depending on the failure or success of blunting of the hemodynamic response, respectively. Success was defined as a change in heart rate and blood pressure by <20% below the baseline at 1, 3, and 5 min after intubation. ED50 and ED95 were analyzed using R statistical software. ED50s of fentanyl in groups 1 (20–35 years), 2 (36–50 years), 3 (51–65 years), and 4 (66–80 years) were 2 μg/kg (90% confidence interval, 1.50–2.50), 2.25 μg/kg (2.00–2.50), 1.89 μg/kg (1.54–2.21), and 1.27 μg/kg (0.72–1.82), respectively. ED95s in groups 1, 2, 3, and 4 were 2.45 μg/kg (2.32–2.96), 2.79 μg/kg (2.58–4.38), 2.44 μg/kg (2.33–3.06), and 2.70 μg/kg (2.30–5.18), respectively. There was a statistically significant incidence of cough in group 2. Patients aged 65–80 years required the lowest ED50 of fentanyl dose, whereas patients aged 36–50 years required the highest ED50 and ED95 dose to blunt the hemodynamic response during intubation.