Leukocytes, the unintended passengers of allogeneic blood products, may very well predispose patients to post-op infections by virtue of their immuno-suppressive effects. Moreover, relatively fresh component blood products like red cells, platelets and freshly prepared frozen plasma may contribute to post-pump pulmonary dysfunction as we will soon see (referring to Komai. ‘98).
Autologous blood, activated by the process of CPB, may be problematic when reinfused into organs that have been rendered ischemic. This so-called “reperfusion injury’ is well-characterized but the myriad ways in which leukocytes are presented to tissues at risk are not well appreciated. Circuit blood is known to contain activated neutrophils and can lead to ‘pump-lung’. Less appreciated is the potential to compromise myocardial preservation with successive doses of blood cardioplegia following the first dose. Each successive dose puts activated neutrophils in the presence of relatively ischemic myocardium.
Finally, far less appreciated is the content of leukocytes present in salvaged blood. Even intraoperatively salvaged, concentrated and washed blood contains a far greater burden of leukocytes than is generally appreciated by clinicians. When reinfused into the patients shortly after pulmonary vasculature reperfusion, the likelihood of exacerbating lung injury is high.