Dexmedetomidine as an Anaesthetic Adjunct in Patients Undergoing Elective Off-Pump Coronary Artery Bypass Graft Surgery

Abstract

Background: The aim of the present study was to study the hemodynamic profile of dexmedetomidine during induction and distal anastomosis of coronary arteries in patients undergoing OPCAB in comparison to the institutional practice of using midazolam. Methods: In Group I, (n=25) patients were anaesthetised using fentanyl, pancuronium bromide, Isoflurane and midazolam. Group II (n=25) patients received a loading dose of dexmedetomidine infusion (1µg/Kg) over 10 minutes followed by an infusion of dexmedetomidine at the rate of 0.6 µg/Kg/hour, along with fentanyl, Pancuronium bromide and isoflurane. Heart rate (HR) mean arterial pressure (MAP), pulmonary artery (PA) catheter derived data and BIS were recorded at baseline, at 1 and 3 minutes after induction, at 1, 3 and 5 minutes after intubation, and at 5 and 30 minutes after protamine administration. MAP and HR were recorded every 10 min during the operation, except during distal anastomosis of the coronary arteries when it was recorded every 5 minutes after application of the Octopus tissue stabilising system. Results: The intubation response by way of increase in HR was much less in group II and stabilized by 5 min after intubation. The accompanying hypotension at 1 minute after induction was more in group II, but it was clinically acceptable (81.68±21.74 mm Hg). During distal graft anastomoses HR was in the range of 68 beats/min to 85 beats/min in group II vs. 85 beats/min to 100 beats/min in Group I. The MAP was lower in this group during the distal anastomosis, but it was within clinically acceptable range (> 65 mm Hg). Conclusion: Dexmedetomidine is a viable option as an anaesthetic adjunct in a loading dose of 1µg/Kg followed by an infusion of 0.6 µg/Kg. Future studies will be necessary to show if this provides any outcome benefits.