Patterns of blood response during cardiopulmonary bypass.

Monitoring of cardiopulmonary bypass (CPB) in terms of alterations to the concentrations of selected blood constituents leads to contrasting patterns of response. This has been verified by determining the influence of CPB on the activation of fibrinolysis, complement, leucocytes and the contact phase of coagulation. Fibrinolytic activity was determined by fibrin degradation products (X-FDP's), complement activation by C3a and C5a, leucocyte activation by granulocyte elastase and contact activation by factor XII-like activity (FXIIA). Five patients undergoing elective coronary artery surgery using a bubble oxygenator and pulsatile perfusion were studied. X-FDP's rose gradually during CPB and remained elevated. Similar patterns were observed for elastase and FXIIA. In contrast, C3a rose sharply with peak values at 1 1/2-2h of bypass while C5a did not show significant changes during bypass. The data obtained have enabled the establishment of response patterns for parameters in CPB which will provide information relevant to the clinical application of biomaterials.