Comparative Study of Etomidate and Midazolam with Fentanyl as Inducing Agents in Patients Undergoing Off-pump Coronary Artery Bypass Graft Surgery

Abstract

Introduction: Off-pump Coronary Artery Bypass Graft (CABG) surgery has promising out come with minimal morbidity and mortality. Conduction of anaesthesia is still a challenge in Coronary Artery Disease (CAD) patients. Agents used for induction of general anaesthesia adversely effects haemodynamics. Etomidate is considered the agent of choice in such patients but it has its own adverse effect. Aim: To compare etomidate and midazolam-fentanyl as inducing agents in patients undergoing off-pump CABG and to monitor the haemodynamic changes during induction, laryngoscopy and intubation. Materials and Methods: Patients of both sex with CAD registered for CABG of age between 40 to 80 year and American Society of Anesthesiologist (ASA) grading I-IV, were divided in two groups (n=30). All patients received morphine 0.2 mg/kg intramuscularly 30 minutes before entering operation theatre. Group I patients received etomidate 0.5 mg/kg intravenously and Group II patients received midazolam 0.1 mg/kg+fentanyl 5 µg/kg slow intravenously for induction. The laryngoscopy and intubation was facilitated with rocuronium bromide 0.9 mg/kg and anaesthesia was maintained with O2 and N2 O in 1:2 ratio with isoflurane 0.6%. The chi-square test was used. All the statistical analysis was carried out by using SPSS 16.0 version. Results: Heart rate was lower in Group I (71.00±5.00 beat/ minutes) as compared to Group II (76.87±7.16 beat/minutes). In both the group maximum decline was observed after induction but before intubation and maximum increase at one minute after intubation. Systolic Blood Pressure (SBP) (135.4±8.00 and 127.93±12.95 mmHg) and Diastolic Blood Pressure (DBP) (72.20±6.31 and 62.73±7.03 mmHg) were significantly lower before induction (82.13±7.22 and 87.00±6.10) respectively. The SBP (147.20±80 and 158±8.39 mmHg) and DBP (83.67±7.28 and 90.40±5.49) were significantly rise after one minute intubation and gradually lower to baseline approximately 10 minutes after intubation in both groups. Conclusion: In both the groups variation in haemodynamic was in the same trend but range of variation was less (10%) in patients induced with etomidate, and more in patients induced with midazolam and fentanyl (20-30%).

Keywords

• coronary artery disease
• general anaesthesia
• haemodynamics
• intubation
• laryngoscopy