[Effect of an intravenous nitroglycerin bolus on the hemodynamic impact of laryngoscopy and intubation].

The aim of this study was to evaluate the effectiveness of intravenous administration of a single dose of nitroglycerin in lessening the hemodynamic effects induced during laryngoscopy and tracheal intubation. In an initial subset of 8 patients we verified that the hemodynamic changes after an intravenous dose of 2, 5, or 10 micrograms/kg of nitroglycerin were comparable. The study included 30 patients with a good clinical condition who were anesthetized with fentanyl, thiopental sodium and succinylcholine. They were allocated into two groups of 15 patients according to the intravenous administration or not of 2 micrograms/kg of nitroglycerin after induction of anesthesia. Increase in systolic blood pressure (SBP) and double product (SBP x heart rate) during laryngoscopy and 15, 30, and 45 seconds thereafter was significantly lower in nitroglycerin treated patients than in controls. Increase in diastolic blood pressure was also lower in nitroglycerin treated patients but this difference was only present during laryngoscopy. There were no significant heart rate differences among the two groups of patients. It is concluded that a single intravenous dose of 2 micrograms/kg of nitroglycerin was able to lessen the increase in blood pressure induced by laryngoscopy and tracheal intubation without deleterious effects.