Evaluation of Clonidine and Lignocaine for Attenuation of Haemodynamic Response to Laryngoscopy and Intubation: A Randomised Controlled Trial

Introduction: Laryngoscopy and intubation leads to stimulation of the laryngopharyngeal and tracheal structures which leads to reflex sympathetic response and sudden rise of Blood Pressure (BP) and Heart Rate (HR). This sudden rise, particularly in patients with cardiovascular and cerebrovascular diseases, can lead to precipitation of Myocardial ischaemia or heart failure. Drugs like fentanyl, esmolol, lignocaine, clonidine when given before the procedure can blunt this reflex, but their response varies widely. Aim: To compare the efficacy of lignocaine and clonidine in attenuating BP and HR response to intubation. Materials and Methods: The study was a double-blind randomised controlled trial was conducted in Operation Theatre (OT) of Indian Spinal Injuries Centre, New Delhi, India (between March 2009 to April 2011). After taking an informed consent, 105 patients of American Society of Anaesthesiologists (ASA) Grade I and II were randomised into three groups: a) Lignocaine; b) Clonidine and c) control group with Normal Saline (NS) and outcome of 90 patients was noted. The drugs were given by IV route before induction of anaesthesia and vital parameters before and after intubation were noted. An anaesthesiologist who was blinded to the study drugs for each group gave the drugs. Statistical analysis was done using Paired t-test, ANOVA, Duncan’s multiple range test. Significant p-value was considered less than 0.05. Results: The rise in BP and HR from baseline to one minute after intubation, was significantly less in both lignocaine and clonidine groups, as compared to the control. Conclusion: Both lignocaine and clonidine can be used to attenuate the haemodynamic response however, lignocaine seems to be better in maintaining vitals around baseline level and rise and fall of BP and HR is less.