The Effect of Low-Dose of Ketamine Infusion on Stress Responses in Coronary Artery Bypass Graft Surgery

Background: Open heart surgery is associated with acute perioperative changes in plasma levels of neurohormonal stress factors,cortisol,interleukin-6 and C-reactive protein. Human studies involving cardiopulmonary bypass have shown that very low doses of ketamine can attenuate the markers of inflammation without adverse effects. The aim of this study was to investigate whether, low dose infusion of ketamine when administered during 48 hours after induction , have anti-inflammatory effect and attenuate stress factors, in on-pump coronary artery bypass graft surgery. Methods: In this prospective randomized-controlled trial, 50 patients undergoing on-pump coronary artery bypass graft were randomly assigned to receive either 1.25mcg/kg/min of ketamine (Ketamine group, n=25) or normal saline (Control group, n=25) infusion during and for 48 hours after surgery. Inflammatory and stress response markers including C-reactive protein, cortisol, White blood cell count and differential , glucose and lactate level were measured ,before induction (T1), 4 hours after surgery (T2), and on the first and the second days after surgery (T3 and T4). Results: The level of lactate were higher in ketamine compared with control group four hours after operation (P < 0.05) without any significant differences detected in other measurements. Conclusion: Low dose ketamine did not cause any change in C-reactive protein, cortisol, White blood cell count and glucose level, however lactate level was higher compared to control group.