AUTOTRANSFUSED SHED MEDIASTINAL BLOOD HAS NORMAL ERYTHROCYTE SURVIVAL

Background. Autotransfusion of shed mediastinal blood may reduce the n eed for homologous blood transfusions in cardiac surgery. In an earlie r study we have shown that the red blood cells (RBCs) of shed mediasti nal blood have a normal membrane stability (osmotic fragility) compare d with circulating RBCs after coronary artery bypass grafting and bett er than stored RBCs. This indicates that RBCs in shed mediastinal bloo d are not damaged further during salvage. It remains to be determined how autotransfusion affects the survival of RBCs from shed mediastinal blood. Methods. We performed a prospective, randomized, and controlle d study involving 26 patients having elective, uncomplicated coronary artery bypass grafting. Dual-isotope labeling technique (chromium 51 a nd technetium 99m) was used to investigate the 24-hour survival of RBC s from shed mediastinal blood and RBCs from circulating blood, and to estimate the mean survival time of RBCs. Results. There was no signifi cant difference between the 24-hour survival of shed mediastinal RBCs and circulating RBCs. The estimated mean cell lifespan was 20.5 days ( range, 11.6 to 29.0 days) for shed mediastinal RBCs and 22.7 days (ran ge, 14.4 to 36.2 days) for circulating RBCs. Conclusions. The survival of RBCs from shed mediastinal blood after autotransfusion is comparab le with the survival of RBCs in the patients' circulating blood.