BACKGROUND Laryngoscopy and endotracheal intubation are very essential tools in the hands of an anaesthesiologist in securing & maintaining the air way & administration of general anaesthesia. Direct laryngoscopy and endotracheal intubation are noxious stimuli that can lead to adverse response of cardiovascular, respiratory and other systems. Reid and Bruce, in the year 1904 & King Harris in 1951 described the circulatory response following laryngoscopy & tracheal intubation due to the stimulation of larynx and trachea as reflex sympatho-adrenal system. 1,2 METHODS 150 normotensive adult consenting patients aged 20-15 years, ASA grade 1 and grade 2 of both genders, were randomized into two treatment groups of 75 patients each. Group A patients received tablet of Gabapentin 900 mg and group B patients received tablet of Clonidine 200 micrograms, 120 minutes before surgery. 150 patients were randomly divided into two equal groups of 75 each namely group A and group B. Anaesthetic technique was standardized and all groups were assessed for haemodynamic changes before administration of study drug (t1), just before taking the patients in OT (t2), before intubation (t3), after intubation (t4), 0 minutes, 3 minutes, 5 minutes, 10 minutes, 30 minutes after intubation. RESULTS Significantly decreased heart rate, systolic blood pressure, diastolic blood pressure, mean arterial blood pressure and pulse pressure product were observed in both group A and group B, after laryngoscopy and intubation. CONCLUSIONS Gabapentin 900 mg attenuates the pressure response due to laryngoscopy and intubation better than Clonidine 200 mg. However, the attenuation of heart rate in both groups is similar.

Laryngoscopy and intubation violates the patient's protective airway reflexes and lead to physiological changes involving various systems of the body. Reflex changes in the cardiovascular system are most marked after laryngoscopy and intubation and leads to average increase in blood pressure by 40-50% and 20% increase in heart rate (Indian J. Anaest 2002) 45(2):104-106. The present study compare the safe and clinically effective intravenous bolus dose of labetalol and lignocaine for controlling the cardiovascular response to laryngoscopy and intubation. METHODSA total of 90 normotensive adult consented patients aged 20-50 years, ASA grade I and grade II of both gender were randomized into three treatment groups of 30 patients each. Group I received normal saline 10 mL as infusion. Group II received 1.5 mg/kg body wt. of lignocaine hydrochloride one minute before intubation. Group III received 0.4 mg/kg body wt. of labetalol hydrochloride 5 minutes before intubation respectively. Anaesthetic technique was standardized and all groups were assessed for haemodynamic changes after the premedication before and after intubation, at the 1 st , 3 rd , 5 th and 10 th minute after intubation along with intraoperative haemodynamic stability and post-operative side effects. RESULTSSignificant increase in heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure were observed in group I after laryngoscopy and intubation. Statistically significant alteration of heart rate, systolic blood pressure and mean arterial pressure but no significant effect in the rise of diastolic blood pressure was observed respectively in group II, whereas statistically highly significant alternation of heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure were recorded in Group III. CONCLUSIONIntravenous bolus dose of labetalol is superior to lignocaine in attenuating the cardiovascular response to laryngoscopy and intubation. The study patients were haemodynamically stable perioperatively without prolongation of recovery time and side effects. KEYWORDSLabetalol, Lignocaine, Laryngoscopy, Intubation. HOW TO CITE THIS ARTICLE:Tayung RP, Laha AK, Talukdar TK, et al. Effect of intravenous labetalol in controlling the cardiovascular response to laryngoscopy and intubation: a comparison with intravenous lignocaine.