A Comparative Study of Intravenous Esmolol, Labetalol and Lignocaine in Low Doses for Attenuation of Sympathomimetic Responses to Laryngoscopy and Endotracheal Intubation

BACKGROUND: Direct layngoscopy and endotracheal intubation is a noxious stimuli and induces sympathomimetic responses. Although well tolerated in healthy subjects, it may impose life threatening arrhythmias, left ventricular failure or rupture of cerebral aneurysm in susceptible patients. Esmolol, Labetalol and Lignocaine attenuate these responses but are associated with side effects of bradycardia, hypotension etc. In lower doses, chances of these side effects are comparatively low. So we designed this prospective clinical trial to assess the efficacy of intravenous esmolol, labetalol and lignocaine in low doses for attenuation of sympathomimetic responses to endotracheal intubation. MATERIALS AND METHODS: Seventy-five consenting patients of ASA physical status I or II of age range 20 to 60 years, scheduled for different general surgical procedures were randomly assigned to one of the three groups; group ES, group LB and group LG. Participants of group ES, group LB and group LG was given esmolol HCL 0.5 mg/Kg, labetalol HCL 0.25 mg/kg and lignocaine HCL 1 mg/Kg body weight respectively. Outcome variables were HR, SBP, DBP, MAP and RPP. These variables were recorded just after intubation and thereafter at 1,3,5, 7 and 10 minutes of intubation. RESULTS: There was no statistically significant difference regarding the demographic characteristics of the groups. Heart rate and systolic blood pressure was lower throughout the study period in labetalol group. But the values of study parameters were always higher than the baseline in esmolol and lignocaine group. Values of mean arterial pressure was slightly higher in labetalol group but it was much higher in two other groups throughout the study period. Diastolic blood pressure was higher in all the groups. Values of rate pressure product was higher during intubation and at 1minute after intubation in labetalol group but thereafter it was always lower than baseline values. CONCLUSION: Labetalol 0.25 mg Kg(-1) is an effective and safe drug to be used for attenuation of sympathomimetic responses to endotracheal intubation. Esmolol 0.5 mg Kg(-1) and lignocaine 1 mg Kg(-1) are also effective to some extent and are safe.