Age may influence fentanyl dose required to effectively control hemodynamic stress response during intubation, suggests study

Endotracheal intubation can trigger temporary hypertension, tachycardia, arrhythmia, increased intracranial pressure, and increased intraocular pressure, despite a patient receiving an anesthetic induction. This effect is particularly concerning for patients with coronary artery disease, as it can lead to cardiac arrhythmias, acute subendocardial ischemia, and hypertension.

Recent study aimed to determine the effect of age on the median effective dose (ED50) and 95% effective dose (ED95) of intravenous fentanyl for blunting the hemodynamic response to tracheal intubation, as well as investigate the associated side effects. The study enrolled 86 patients aged 20-80 years undergoing general anesthesia and neurological surgery. Patients were randomly stratified into 4 age groups: 20-35 years, 36-50 years, 51-65 years, and 66-80 years. Fentanyl was administered intravenously in each patient according to the Dixon and Massey up-and-down method, starting at 2 μg/kg. The dose was increased or decreased by 0.5 μg/kg for the subsequent patient depending on the success or failure of blunting the hemodynamic response, respectively. Success was defined as a change in heart rate and blood pressure of less than 20% from baseline at 1, 3, and 5 minutes after intubation.

The results showed that the ED50 of fentanyl was lowest in the 66-80 year old age group at 1.27 μg/kg, while the 36-50 year old group required the highest ED50 and ED95 at 2.25 μg/kg and 2.79 μg/kg, respectively. There was a statistically significant incidence of cough in the 36-50 year old group compared to the other groups, but no other significant differences in adverse events such as hypotension, bradycardia, arrhythmia, respiratory depression, nausea, or vomiting. In conclusion, elderly patients aged 65-80 years required the lowest dose of fentanyl to blunt the hemodynamic response to intubation, while those aged 36-50 years required the highest dose. The findings suggest that age influences the fentanyl dose required to effectively control the hemodynamic stress response during intubation, with elderly patients needing lower doses. Careful titration of fentanyl dosage based on patient age is important to prevent complications, especially in high-risk patients with cardiovascular or neurological conditions.

Key Points

Here is a detailed summary of the key points from the research paper in 6 bullet points:

- The study aimed to determine the effect of age on the median effective dose (ED50) and 95% effective dose (ED95) of intravenous fentanyl for blunting the hemodynamic response to tracheal intubation, as well as investigate the associated side effects.

- The study enrolled 86 patients aged 20-80 years undergoing general anesthesia and neurological surgery, who were randomly stratified into 4 age groups: 20-35 years, 36-50 years, 51-65 years, and 66-80 years.

- Fentanyl was administered intravenously using the Dixon and Massey up-and-down method, starting at 2 μg/kg and adjusting the dose by 0.5 μg/kg for subsequent patients based on the success or failure of blunting the hemodynamic response.

- The results showed that the ED50 of fentanyl was lowest in the 66-80 year old age group at 1.27 μg/kg, while the 36-50 year old group required the highest ED50 and ED95 at 2.25 μg/kg and 2.79 μg/kg, respectively.

- There was a statistically significant incidence of cough in the 36-50 year old group compared to the other groups, but no other significant differences in adverse events such as hypotension, bradycardia, arrhythmia, respiratory depression, nausea, or vomiting.

- The findings suggest that age influences the fentanyl dose required to effectively control the hemodynamic stress response during intubation, with elderly patients needing lower doses, and careful titration of fentanyl dosage based on patient age is important to prevent complications.

Reference –

Eiamcharoenwit J, Akavipat P. 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. J Anaesthesiol Clin Pharmacol 2024. DOI:10.4103/joacp.joacp_280_23