Comparative study of intravenous 2% lignocaine versus metoprolol to attenuate pressor response to laryngoscopy

Introduction: Laryngoscopy and endotracheal intubation are associated with reflex sympathetic stimulation known as pressor response. Transient haemodynamic instability, an inevitable outcome of laryngoscopy can have serious effects especially in patients with heart disease, hypertension which can cause major complications. We compared the attenuating effect of time – tested lignocaine versus metoprolol on the haemodynamic response to laryngoscopy and intubation in normotensive patients undergoing general anaesthesia for spine surgeries. Method: After the approval of the institutional ethical committee, written informed consent was obtained from each patient. 60 patients who satisfied the inclusion criteria were divided into two groups Group L (n= 30) received Inj. Lignocaine 1.5 mg/ kg IV before induction and Group M (n= 30) received Inj. Metoprolol 0.1 mg/ kg intravenous before induction HR, SBP, DBP, MAP were recorded at baseline sedation, post induction, at laryngoscopy and post intubation and 0.5, 1, 2, 5 and 10 minutes post intubation. Statistical Analysis: Data was analysed using Paired Students ‘t’ test for intra group (within the group) variation, Unpaired student’s ‘t’ test for inter group (between the 2 groups) variation. Analysis of variance (ANOVA) for comparison between different baseline variables (age, weight, HR, SBP, DBP, MAP and RPP). Value of P < 0.05 was considered significant. Results: In lignocaine group, there was a significant increase in heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure and rate pressure product in response to laryngoscopy and intubation. Values continued to remain high even after 5 minutes of post intubation as compared to metoprolol group. Conclusion: Intravenous metoprolol 0.1 mg/ kg given 5 minutes prior to laryngoscopy and intubation successfully attenuated the pressor response to laryngoscopy and intubation. In addition, it was found to be safer and more effective than intravenous lignocaine 2%.