Different profile of antioxidative capacity results in pulmonary dysfunction and amplified inflammatory response...

Respiratory complications after cardiosurgical interventions are frequent and cause severe problems, postoperatively. The present study addresses the question for group-specific release of radical oxygen species (ROS) by extracorporeal circulation (ECC) with emphasis on pulmonary function.

Fifty-one patients who had undergone bypass surgery were evaluated for serum antioxidative capacity (AOC). Blood gas analysis, leukocyte counts, C-reactive protein (CRP), and hemodynamic data cardiac output (CO), pulmonary capillary wedge pressure (PCWP) arterial-alveolar gradient (AaDO(2)), and Murray scores were measured after ECC up to 48 h. According to AOC levels at baseline before ECC, patients were divided into two groups (group A: "high" AOC equal to or above median of the whole sample; n=26; versus group B: "low" AOC below median; n=25).

A different time course in AOC could be detected between both groups. Both groups had an improvement in postoperative cardiac output evaluation, but in group A (high AOC) the PCWP was reduced (P=0.015). In this group, an increased AaDO(2) and elevated Murray score were seen 12 h postoperatively (P<0.001), suggesting reduced oxygen uptake. Moreover, increased CRP values and a trend to reduced leukocyte counts indicate differences in amplified inflammatory response to ECC.

Free radical production after ECC is not a uniform process. Preoperative differences in AOC indicate interindividual variations. The surgical trauma results in a clear decrease of AOC in group A, while in group B AOC showed no major changes. As shown for reduced PCWP, release of ROS can affect pulmonary function. Therefore, AOC may be a useful parameter for prediction of postoperative complications.