CHELATABLE IRON AND COPPER CAN BE RELEASED FROM EXTRACORPOREALLY CIRCULATED BLOOD DURING CARDIOPULMONARY BYPASS

During cardiopulmonary bypass surgery blood is extracorporeally oxygen ated and circulated before returning to the systemic arterial circulat ion. Blood undergoing extracorporeal dilution and circulation is expos ed to non-physiological surfaces, which cause the activation of severa l regulatory cascades. Cells are also subjected to damaging shear stre sses. Under such conditions neutrophils can be 'activated' to release reactive oxygen intermediates such as O2- and H2O2, and other cells ca n release proteolytic enzymes and metalloproteins. Collectively, these events can result in the release of micromolar quantities of redox ac tive iron and copper. Bleomycin-detectable iron and phenanthroline-det ectable copper were found in two out of four mock bypass experiments. However, there was no correlation between the presence of chelatable i ron and copper and the activation of neutrophils measured as elastase.