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.

BACKGROUND AND AIMS

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.

MATERIAL AND METHODS

Patients ( = 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.

RESULTS

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.

CONCLUSIONS

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.