Attenuation of cardiovascular response to laryngoscopy and tracheal intubation by a bolus dose of inj. esmolol and placebo – A comparative study

Introduction and Objectives: Laryngoscopy and tracheal intubation are noxious stimuli that produce marked sympathetic responses manifesting as tachycardia and hypertension, which can be deleterious in susceptible-patients if they precipitate myocardial ischaemia, infarction, arrhythmias etc. Since β-blockers counteract these sympathetic activation, this clinical study was designed to evaluate and compare a short-acting β-blocker, Esmolol as IV bolus to a placebo in attenuating sympathetic responses at laryngoscopy and intubation in healthy adults. Materials and Methods: This was a randomized prospective controlled study consisting of 60 patients who were allocated into group A (Esmolol) and Group B (Placebo). Patients were premedicated with glycopyrolate 0.2 mg IV 90 minutes before surgery. Esmolol was given as 100 mg IV bolus immediately before induction with Thiopentone 5 mg/kg and Suxamethonium 1.5 mg/kg. The study period extended up to 5 minutes after intubation. Pre-induction readings of Heart rate, Systolic blood pressure, Diastolic blood pressure, mean arterial pressure and Rate pressure product were compared to those at 1st, 3rd and 5th minutes after intubation. Changes in ECG and any other adverse effects were looked for. Results: The mean values of Heart rate, Systolic blood pressure, Diastolic blood pressure, Mean arterial pressure and Rate pressure product for esmolol group at pre-induction, at 1st, 3rd and 5th minute were noted to be as follows: (Figures in parenthesis for placebo). Heart rate (b/min) was 87.93 (86.03), 87.37 (102.03), 88.40 (100.77), 88.13 (98.63); Systolic blood pressure (mmHg) was 130.93 (128.33), 128.80 (145.73), 122.80 (136.13), 121.80 (130.80); Diastolic blood pressure (mmHg) 81.40 (79.87), 79.00 (97.87), 78.07 (87.80), 78.67 (85.13); Mean arterial pressure (mmHg) was 97.35 (94.91), 94.03 (114.42), 93.01 (103.84), 92.68 (100.57) and Rate pressure product was 11323.60 (11042.50), 10831.6 (14971.4), 10826.8 (13817.9), 10779.9 (12896.6) respectively. There were neither significant adverse effects nor ECG changes. Interpretation and Conclusion: Esmolol 100 mg IV bolus effectively attenuates sympathetic responses at laryngoscopy and tracheal intubation without any adverse effects.