Influence of antioxidants (mannitol and allopurinol) on oxygen free radical generation during and after cardiopulmonary bypass.
Oxygen-derived free radicals (O2-, H2O2, OH.) are produced during oxidative metabolism, ischemia and reperfusion, and cardiopulmonary bypass (CPB). When oxygen free radical production exceeds scavenging capacity, peroxidation of structural lipids in cell membranes can occur with potentially injurious consequences. In this prospective study, 45 patients were evaluated to determine the effect of CPB on oxygen free radical generation. Twenty patients in group I were controls. Exogenous oxygen free radical antioxidants were administered before bypass to patients in group II (n = 15, mannitol) and group III (n = 10, allopurinol). In group I, plasma H2O2 increased during extracorporeal circulation from 65 +/- 6.0 to 125 +/- 12 microM/ml (p less than .001). At similar sampling intervals, plasma H2O2 levels were significantly lower in group II (p less than .03) and group III (p less than .05) when compared with those in group I. Red blood cell H2O2 did not change in group I or group II. White blood cell H2O2 levels decreased in group I (p less than .04) and group II during CPB. (Intracellular concentrations of H2O2 were not obtained in group III patients). We conclude that cytotoxic oxygen radicals are generated during CPB and that pretreatment with free radical antioxidants, mannitol or allopurinol, may minimize the free radicals available for lipid peroxidation of biomembranes.
D000493:Allopurinol / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D002315:Cardiopulmonary Bypass; D004912:Erythrocytes / Q000378:metabolism; D005609:Free Radicals; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D007432:Intraoperative Period; D007962:Leukocytes / Q000378:metabolism; D008353:Mannitol / Q000494:pharmacology*; D010100:Oxygen; D011184:Postoperative Period
D000975:Antioxidants; D005609:Free Radicals; D008353:Mannitol; D000493:Allopurinol; D006861:Hydrogen Peroxide; D010100:Oxygen