Infusion Versus Bolus Esmolol on Hemodynamic Responses to Intubation in Patients Undergoing Coronary Artery Bypasses Grafting: a Randomized Clinical Trial

Background & Objective: Perioperative myocardial ischemia remains one of the most serious complications of cardiac surgery. This study aimed to evaluate the effect of bolus esmolol versus its infusion on hemodynamic responses after laryngoscopy and intubation in patients undergoing coronary artery bypass grafting (CABG). Materials & Methods: This double-blind randomized clinical trial was conducted on 75 patients that were allocated into three groups. In the infusion group, 10 minutes prior to laryngoscopy 0.5 mg/kg esmolol was injected, and then, 200 μg/kg/minute esmolol was infused. In the bolus group, 2 minutes prior to the laryngoscopy 1.5 mg/kg bolus dose of esmolol was injected intravenously. In the control group, a bolus dose of normal saline was administered. Heart rate (HR), Systolic (SBP) and diastolic (DBP) blood pressures and mean arterial pressure (MAP), were recorded every one minute from 10 minutes prior to laryngoscopy to 10 minutes after intubation. Repeated measure ANOVA was applied as statistical analysis. Results: SBP was at the lowest rate since laryngoscopy was started until 10 minutes after intubation in the esmolol infusion group (P= 0.029). From the initiation of laryngoscopy to 6 minutes after the intubation, DBP was at the lowest rate in the infusion group. There was a significant difference between the groups regarding DBP changes during the measurement. ANOVA model showed that interaction between time and groups on SBP, MAP, and HR (P< 0.05). Conclusion: According to our results, the exact doses of esmolol infusion significantly reduced the level of SBP during intubation, compared with bolus esmolol.