A Double Blind Comparative Study of Efficacy of Intravenous Magnesium Sulphate with Lignocaine and Intravenous Clonidine with Lignocaine in Attenuating Hemodynamic Response to Laryngoscopy and Tracheal Intubation during General Anaesthesia

Background and objectives: Laryngoscopy and tracheal intubation is invariably associated with a reflex sympathetic pressor response resulting in elevated heart rate and blood pressures. This may prove detrimental in high risk patients. The main objectives of the present study are: To study the effect of intravenous magnesium sulphate 30 mg/kg with intravenous lignocaine 1.5mg/kg, and intravenous clonidine 3mcg/kg with intravenous  lignocaine 1.5mg/kg on changes in the Systolic blood pressure (SBP), Diastolic blood pressure (DBP) and Mean arterial blood pressure (MAP) during laryngoscopy and intubation under general anesthesia. Methods: 60 ASA I and II status normotensive patients scheduled for elective surgical Procedures were selected randomly and divided into three groups of 20 each. All patients received premedication with study drug. Induction of anesthesia was standardized for all patients who received, thiopentone 5 mg/kg i.v. and preservative free lignoaine 1.5mg i.v and were relaxed with succinylcholine 2mg/kg i.v. and laryngoscopy and intubation is done with appropriate sized endotracheal tube. HR, systolic, diastolic blood pressure were recorded noninvasively before induction, postintubation, 1,3,5,7 and 10 minutes from the onset of laryngoscopy. ‘z’ test was used for statistical analysis. Results: The basal and pre laryngoscopy mean SBP and standard deviations in CL group were 122.15 +/- 8.12 and114.50 +/- 7.30 respectively. In ML group basal systolic blood pressure was 117.30 -+-/- 9.78. After giving study drug prelaryngoscopy SBP decreased by 3mm of mm Hg to 114.15 +1- 15.26. Conclusion: Both study drugs were more effective in attenuation of pressor response to intubation than when lignocaine alone was used. Key words: Attenuation, Pressor response, Laryngoscopy, Intubation, Lignocaine, Magnesium sulphate, Clonidines