AUTOTRANSFUSION AFTER OPEN-HEART-SURGERY - QUALITY OF SHED MEDIASTINAL BLOOD COMPARED TO BANKED BLOOD

The need to conserve a patient's own blood and avoid homologous transf usion is now well recognized. Therefore, techniques designed to reduce requirements for homologous blood transfusions have been developed. O ne of the methods is autotransfusion of shed mediastinal blood after o pen-heart surgery. The objectives of the present study were to investi gate osmotic fragility and oxygen transport capacity of shed mediastin al blood compared to patient blood and stored packed red blood cells ( SAGM). Shed mediastinal blood from ten consecutive patients undergoing elective cardiac surgery (coronary bypass grafting) was studied and c ompared to patient blood; 10 units of 3 weeks old and 10 units of 5 we eks old stored packed red blood cells (SAGM). Oxygen transport capacit y was investigated by calculation of p50 for oxygen by use of the oxyg en status algorithm (OSA 2.0) programme and measurement of 2,3-diphosp hoglycerate (2,3-DPG) concentrations. The osmotic fragility was determ ined using increasing concentrations of saline. 2,3-DPG concentrations in shed mediastinal blood (5.3 mikromol/ml erythrocyte) were within t he range measured in patient blood, but significantly higher than SAGM blood (P<0.001). P50 for oxygen (3.5 kPa) in shed mediastinal blood w as not significantly different compared to patient blood, but signific antly higher (P<0.01) compared with stored SAGM blood. The osmotic fra gility in shed mediastinal blood was not significantly different compa red to patient blood, but significantly lower (P<0.001) than the osmot ic fragility in stored SAGM blood. This suggests that red cells saved from shed mediastinal blood have better oxygen transport capacity and may have longer survival compared to stored blood.