Comparison of Three Different Doses of Intranasal Nitroglycerine in Attenuation of Pressor Response to Laryngoscopy and Intubation - A Randomized, Double Blind, Intervention at SMS Hospital Jaipur

Background: Laryngoscopy and endotracheal intubation are associated with a transient but marked sympathoadrenal response, manifested by increases in heart rate and blood pressure. Excessive hemodynamic stress can precipitate complications in susceptible individuals. Various pharmacological interventions, including opioids, local anesthetics, and vasodilators, have been investigated to blunt this response. Nitroglycerine (NTG) administered intranasally may attenuate this pressor response via rapid absorption and vasodilatory effects. Methods: In this randomized, double-blind, interventional study, 138 normotensive adult patients undergoing elective surgery under general anesthesia were allocated into three groups (46 in each). Patients in Group A received 400 µg intranasal NTG, Group B received 800 µg, and Group C received 1200 µg. Hemodynamic parameters (heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure) were recorded from baseline to 10 minutes post-intubation. Incidence of adverse events (tachycardia, hypotension, nausea) was also noted. Results: All three groups showed an increase in heart rate at laryngoscopy and intubation. The group receiving 1200 µg demonstrated a higher peak heart rate compared to those receiving 400 µg or 800 µg. Conversely, systolic, diastolic, and mean arterial pressures decreased more pronouncedly with the 1200 µg dose compared to the lower doses. By 10 minutes post-intubation, blood pressure in the 1200 µg group was reduced by approximately 18–28% from baseline, while it was 10–21% and 13–24% in the 400 µg and 800 µg groups, respectively. The highest incidence of tachycardia (10.8%) and hypotension (8.7%) occurred with the 1200 µg dose; however, these events were easily managed without significant morbidity. Conclusion: Intranasal nitroglycerine effectively attenuates the pressor response to laryngoscopy and intubation. The 1200 µg dose offers the most pronounced attenuation of blood pressure but carries a higher incidence of side effects. The intermediate dose (800 µg) may provide a favorable balance between efficacy and tolerability.