Sublingual Nitroglycerin spray versus normal saline spray in attenuating pressor response to extubation: Changes in heart rate

Abstract

The sympathetic response involves polysynaptic pathway with Glossopharyngeal and Vagus nerve forming afferent arc to the sympathetic nervous system via brain stem and spinal cord. This causes firing of adrenergic mediators such as norepinephrine and epinephrine which leads to increase in HR and blood pressure. Parasympathetic reflex is monosynaptic and is more common in children. Approval from ethical committee and written informed consent was obtained. A total of 60 patients undergoing surgery under general anaesthesia with endotracheal intubation were included in the study. After having met inclusion and exclusion criteria and having obtained informed consent, patients were randomized based on computer generated randomization table into one of the two groups. Hemodynamic response to extubation increases HR, BP which in turn increases myocardial oxygen demand. Activation of sympathetic nervous system during extubation causes coronary vasoconstriction which in turn reduces coronary blood flow. NTG dilates coronary vessels thereby increases blood flow of coronaries and thus improving oxygen delivery to myocardium which is an added advantage.