High arterial oxygen levels may aggravate oxidative stress associated with CPB (cardiopulmonary bypass). Most cardiac surgery patients have COPD (chronic obstructive pulmonary disease), complicating the relationship of hyperoxia and oxidative stress. In this study the effects of different oxygenation strategies on oxidative balance during CPB in patients with COPD was assessed. Forty patients with COPD underwent elective coronary bypass surgery, using CPB. In 20 patients, high arterial oxygen levels were maintained (PaO2 between 300-400 mm Hg) during CPB, whereas 20 patients underwent normoxic (PaO2 between 100- 200 mm Hg) bypass. Oxidative balance was assessed by measurement of thiobarbituric acid reactive substance, paraoxanase and uric acid levels in blood. Thiobarbituric acid reactive substance, paraoxanase and uric acid levels obtained throughout the study period were similar among the two groups. In both groups, thiobarbituric acid reactive substance, paraoxanase and uric acid levels remained unchanged after CPB, compared to baseline values. High arterial oxygen levels during CPB do not cause alterations in oxidative balance in the blood of COPD patients.

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