Clinical Evaluation of Efficacy and Safety of three Different Doses of Fentanyl to Prevent Hemodynamic Stress Response During Laryngoscopy and Intubation: A Randomized Double Blind Clinical Study

Background: Hemodynamic stress response to laryngoscopy and intubation produces a significant hemodynamic alteration that may adversely affect patients with cardiac and neurological diseases. Fentanyl before induction attenuates hemodynamic stress response. We compared three different doses of fentanyl so as to find the most appropriate dose which prevents the response without adverse consequences. Methods: In this prospective double blind clinical study, 90 patients aged 18 to 40 years of American Society of Anaesthesiologist (ASA) physical status I and II, scheduled for elective surgery under general anaesthesia requiring endo tracheal intubation. Patients were randomised to three groups of 30 patients each, which received 2, 3 or 4 μg/kg of fentanyl intravenously 5 minutes before induction of anaesthesia in group I, II and III respectively. All groups were assessed for pre-operative sedation, hemodynamic changes after premedication, during laryngoscopy and intubation, after intubation at specific timing up to 20 minutes and post-operative side effects. Results: Fentanyl in doses of 3 and 4μg/kg was effective in complete prevention of hemodynamic stress response during laryngoscopy and intubation. However, 4 μg/kg of fentanyl produced a 20-25% decrease in hemodynamic variables from baseline compared to 15-20% with 3 μg/kg of fentanyl. Sedation score at exudation was higher with higher doses of fentanyl. Three patients receiving 4μg/kg of fentanyl required O2 supplementation in immediate post operative period. Conclusion: Fentanyl in dose of 3μg/kg, five minute before induction is the most appropriate dose in terms of efficacy and safety for preventing hemodynamic stress response during laryngoscopy and intubation.