European Journal of Cardiovascular Medicine

Many attempts have been made to attenuate the pressor response to laryngoscopy and endotracheal intubation e.g. deep anaesthesia, topical anaesthesia, use of ganglionic blockers, antihypertensive agents, calcium-channel blockers, fentanyl, lignocaine, magnesium sulphate etc.  Clonidine is mainly used as an anti-hypertensive agent, but has many properties of ideal premedicant and also has beneficial effects on haemodynamics during stressful conditions like laryngoscopy and endotracheal intubation. Different studies have shown that intravenous clonidine is effective in reducing the haemodynamic responses to laryngoscopy and endotracheal intubation on an average dose of 3-4µg/kg body weight. The present study is aimed to observe whether further reduction in dose of clonidine will be effective or not for the same. This study was designed to observe the effects of clonidine hydrochloride infusion on haemodynamic response to laryngoscopy and endotracheal intubation during general anaesthesia in comparison with placebo and to observe any side effect of the study drug. Methods: In this prospective randomized study two groups of 34 patients each were studied. The Group-A received normal saline as study solution and Group-B received 2μg/kg Clonidine as study solution, was infused with an infusion pump over 10 minutes as per randomization table. After completion of infusion General Anaesthesia was administered and haemodynamic variables were noted immediately, one, three and five minutes after intubation. There was rise in all the parameters (HR, SBP, DBP, and MAP) compared to baseline value in both the groups. Inter-group comparison was done with respect to all the above parameters and side effects in both groups were noted. Result: There was rise in mean heart rate which was statistically significant at immediately after LETI compared to baseline within the groups, but the rise was not statistically significant when compared between two groups. Inter-group comparison shows that there was statistically significant lower rise in the study group. Immediately and one minute after LETI the difference in mean systolic blood pressure from baseline was statistically significant but at three and five minute the rise was similar in both the groups. Inter- group comparison shows highly significant difference in rise of diastolic blood pressure between two groups. Mean arterial pressure showed statistically significant rise from baseline at all the point of measurement after LETI in both the group. This rise was significantly less in study group only immediately after LETI. Inter-group comparison at other points of measurement  showed no difference in changes of mean arterial pressure between the groups. Conclusion:  We conclude that pre-induction low dose Clonidine infusion is a reasonable option to attenuate haemodynamic surge following LETI compared to placebo.