Production of thiobarbituric acid-reactive material during experimental cardiopulmonary bypass in cows

Increased levels of thiobarbituric acid (TBA)-reactive material were found in the plasma of cows during experimental cardiopulmonary bypass. The levels of TBA-reactive substance decreased during the postoperative period to levels statistically lower (50%; p less than 0.001) than the preoperative values. The increased TBA reactivity of the plasma is indicative of lipid peroxidation during the perfusion period, owing either to exposure of the blood to increased PO2 or to oxygen radical formation. Activation of phagocytic cells by membrane contact and complement activation can induce phagocytic killing processes with the release of oxygen radicals. Although the absolute neutrophil count increased during the perfusion period, convincing correlation with the TBA reactivity was not found, and the origin of the TBA-reactive material remains speculative.