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DOI: 10.1055/s-2005-922363
Free radical production by extracorporeal circulation affects pulmonary perfusion and oxygen uptake and amplifies inflammatory response
Introduction: Respiratory complications after cardiosurgical interventions very often cause severe postoperative problems resulting in a prolongation of ICU-stay or even respiratory failure. Present study adresses the release of Radical Oxygen Species (ROS) by extracorporeal circulation (ECC) with focus on respiratory function.
Methods: Blood specimen of 52 pts. (according to the informed consent) were sampled preop. and 0.5, 6, 18, and 24 hrs. after CABG- surgery, respectively. Blood gas analysis, Leucocyte counts, CRP and hemodynamic data (CO, PCWP) were correlated to the arterial-alveolar gradient (AaDO2), Murray-Score (PEEP, FiO2). The release of ROS were evaluated by measurement of antioxidative capacity (AOC) in blood serum with a kit of RANDOX (Krefeld, Germany). Data cluster analysis was performed by SPSS (Smirnow-Test, Wilcoxon- and U-Test to each group) resulting in a formation of 2 groups. The cut off of 0.8 AOC-Index was choosen for discreminate analysis between high (A) and low (B) AOC-groups.
Results: As seen, the antioxidative response varies between the groups. Both groups had an improvement in postop. Cardiac Output evaluation, but the PCWP was reduced in group A (p=.015). Moreover, an increased AaDO2 was found 6 hrs. postop. (p=.001) suggesting an reduced oxygen uptake. Increased C-reactive protein in group A indicate an amplified inflammatory response to ECC.
Conclusion: ROS production after ECC is not a unified process. Even under standardized conditions the response to trauma and ischemia is different and affects pulmonary function. Hereby, a endothelial stunning by ROS is likely. Therefore, AOC-index should be integrated in preoperative screening.