Continuous S-(+)- ketamine administration during elective coronary artery bypass graft surgery attenuates pro-inflammatory cytokine response during and after cardiopulmonary bypass

Background. Coronary artery bypass surgery (CABG) with cardiopulmonary bypass (CPB) leads to elevated circulating plasma cytokines. In this prospective randomized study, the effect of an S-(+)-ketamine-based anaesthetic protocol on perioperative plasma cytokine levels was compared with standard anaesthesia with propofol and sufentanil during CPB. Methods. Patients undergoing elective on-pump CABG were randomly allocated to anaesthesia with sufentanil-propofol-midazolam (Sufentanil) or S-(+)-ketamine-propofol-midazolam (Ketamine). Blood samples were obtained before induction of anaesthesia (baseline) and also at 1, 6, and 24 h after aortic unclamping. Plasma levels of the interleukins (IL)-6, IL-8, IL-10, and tumour necrosis factor (TNF)-alpha were determined by enzyme-linked immunosorbent assay. Results. One hundred and twenty-eight patients were studied (Ketamine: n=60; Sufentanil: n=68). All measured cytokines increased during and after CPB. However, the increase in the pro-inflammatory cytokines IL-6 and IL-8 6 h after aortic unclamping was significantly lower in the Ketamine group compared with the Sufentanil group [mean (SD): IL-6 56.75 (46.28) pg ml(-1) (Ketamine) vs 172.64 (149.93) pg ml(-1) (Sufentanil), P<0.01; IL-8 7.74 (14.72) pg ml(-1) (Ketamine) vs 26.3 (47.12) pg ml(-1) (Sufentanil), P<0.01]. In contrast, the anti-inflammatory cytokine IL-10 showed higher levels 1 h after unclamping in the Ketamine group compared with the Sufentanil group [mean (SD): 69.59 (78.78) vs 24.63 (37.7) pg ml(-1), P<0.001]. Conclusion. Our data demonstrate that S-(+)-ketamine possesses anti-inflammatory potential. Anaesthesia with S-(+)-ketamine may have beneficial effects in attenuating the CPB-induced systemic inflammatory response.