Attenuation of Hemodynamic Response to Laryngoscopy and Endotracheal Intubation with Pre Induction IV Fentanyl Versus Combination of IV Fentanyl and Sub Lingual Nitroglycerin Spray

Abstract

Introduction: Endotracheal intubation is one of the most invasive stimuli in anesthesia and it's often accompanied by a hemodynamic pressor response. The purpose of this study was to investigate the efficacy of a single pre-induction 2 µg/kg bolus injection of fentanyl followed by two puffs of nitroglycerin sub lingual spray (400 µg /spray) with a thiopentone/suxamethonium sequence in the attenuation of the hemodynamic response to endotracheal intubation in normotensive patients.

Material and methods: The study consisted of 80 randomly selected ASA physical status I/II male/female adults who were aged between 18 through 60 years and scheduled for elective surgery. Group I received a single 2 µg/kg IV bolus of fentanyl diluted to 5 ml with normal saline 5 min prior to laryngoscopy followed by two puffs of nitroglycerin sub lingual spray (400 µg/spray) 2 minutes prior to intubation (n=40). Group II received a single 2 µg/kg IV bolus of fentanyl diluted to 5 ml with normal saline 5 min prior to laryngoscopy (n=40). Heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure and rate pressure product were compared to basal values at pre-induction, induction, intubation and post-intubation as well as at time increments of 1, 3, 5, 7 and 10 min.

Results: Fentanyl combined with nitroglycerin did not attenuate hemodynamic pressor responses more than fentanyl alone. Increases of HR (7.9%), DBP (4.0%), MAP (3.6%) and RPP (6.0%) along with attenuation of SBP (2.7%) were observed in the fentanyl-nitroglycerin group as compared to the equivalent control measured values.

Conclusions: A single pre-induction bolus injection of fentanyl followed by two puffs of nitroglycerin sub lingual spray in a thiopentone/suxamethonium anesthetic sequence neither successfully attenuates nor successfully suppresses the hemodynamic pressor response more effectively than fentanyl alone in normotensive patients resulting from endotracheal intubation.

Keywords: attenuation; endotracheal intubation; fentanyl; hemodynamic response; nitroglycerin.

Figure 1

A – mean HR values for control and nitroglycerin-fentanyl groups ± SD and B – percent difference between measured HR levels and basal values.

Figure 2

A – mean SBP values for control and nitroglycerin-fentanyl groups ± SD and B – percent difference between measured SBP levels and basal values.

Figure 3

A – mean DBP values for control and nitroglycerin-fentanyl groups ± SD, B – percent difference between measured DBP levels and basal values.

Figure 4

A – mean MAP values for control and nitroglycerin-fentanyl groups ± SD, B – percent difference between measured MAP levels and basal values.

Figure 5

A – mean RPP values for control and nitroglycerin-fentanyl groups ± SD, B – percent difference between measured RPP levels and basal values.