Effect of Dexmedetomidine Infusion on Sublingual Microcirculation in Patients Undergoing On-Pump Coronary Artery Bypass Graft Surgery: A Prospective Randomized Trial

Objectives: Cardiac surgery is characterized by attenuation of microcirculatory perfusion. Dexmedetomidine has been proved to attenuate the microcirculatory derangements evoked by experimental sepsis. The authors investigated the effects of dexmedetomidine infusion on sublingual microcirculation in patients undergoing on-pump coronary artery bypass graft (CABG) surgery. Design: Prospective, randomized blinded study. Settings: Tertiary university hospital. Participants: A total of 70 adults undergoing elective on-pump CABG surgery. Intervention: After a standard general anesthesia, participants were allocated randomly to receive either propofol continuous intravenous infusion, 50 to 70 mu g/kg/min, or propofol infusion, 50 to 70 mu g/kg/min plus dexmedetomidine infusion, 0.5 mu g/kg/h, during cardiopulmonary bypass. Microcirculation was studied with side-stream dark field imaging at 3 times: immediately before starting bypass (T0), 30 minutes after initiation of bypass (T1), and 30 minutes after weaning from bypass (T2). Measurements and Main Results: Microvascular flow index was significantly higher in the dexmedetomidine group at T2 compared to the control group (2.20 +/- 0.29 and 1.47 +/- 0.30, respectively; p = 0.001). The perfused vessel density was significantly higher in the dexmedetomidine group at T2 compared to the control group (6.1 [3-8.9] mm/mm(2) and 3.3 [2.2-4.3] mm/mm(2), respectively; p = 0.01). The total vascular density was significantly higher in the dexmedetomidine group compared to the control group at T1 and T2 (9.9 [7.8-12.6] mm/mm(2) v 7.4 [6.1-9] mm/mm(2), p = 0.005; and 9.27 +/- 2.27 mm/mm(2) v 7.24 +/- 1.66 mm/mm(2), p = 0.003, respectively). Conclusion: This trial demonstrated that dexmedetomidine infusion improved sublingual microcirculation indices in patients undergoing on-pump CABG surgery. (C) 2018 Elsevier Inc. All rights reserved.