The effects of dexmedetomidine on inflammatory mediators after cardiopulmonary bypass

Cardiac surgery with cardiopulmonary bypass is associated with the development of a systemic inflammatory response that can often lead to dysfunction of major organs. We hypothesised that the highly selective α2-adrenergic agonist, dexmedetomidine, attenuates the systemic inflammatory response. Forty-two patients were randomly assigned to receive dexmedetomidine or saline after aortic cross-clamping). The mean (SD) levels of the nuclear protein plasma high-mobility group box 1 increased significantly from 5.1 (2.2) ng ml(-1) during (16.6 (7.3) ng ml(-1) ) and after (14.3 (8.2) ng ml(-1) ) cardiopulmonary bypass in the saline group. In the dexmedetomidine group, the levels increased significantly only during cardiopulmonary bypass (4.0 (1.9) ng ml(-1) baseline vs. 10.8 (2.7) ng ml(-1) ) but not after (7.4 (3.8) ng ml(-1) ). Dexmedetomidine infusion also suppressed the rise in mean (SD) interleukin-6 levels after cardiopulmonary bypass (a rise of 124.5 (72.0) pg ml(-1) vs. 65.3 (30.9) pg ml(-1)). These suppressive effects of dexmedetomidine might be due to the inhibition of nuclear factor kappa B activation and suggest that intra-operative dexmedetomidine may beneficially inhibit inflammatory responses associated with ischaemia-reperfusion injury during cardiopulmonary bypass.