However one of the confounding factors present is that all transfused RBCs are not leukoreduced (unlike the French transfusion policy). In addition, the greater part of the clinical studies are controversial. That is why we aim to assess, through a retrospective study of data, the impact of transfusion of red red blood cells within 14 days of post-operative morbidity and mortality, compared to the usual transfusion practice in cardiac surgery patients.