Microcirculatory hemodynamics after acute blood loss followed by fresh and banked blood transfusion

Background Red blood cell (RBC) conformational changes occur when blood is stored. This study was designed to be a preliminary evaluation to assess how these changes affect the microcirculation. Methods The rat cremaster muscle flap model was used to evaluate in vivo microcirculatory changes after withdrawal of 1 mL blood with subsequent administration of fresh blood (group I, n = 6) and banked blood (group II, n = 6). Each group underwent a 3-stage evaluation: baseline, after blood withdrawal, and after transfusion. Using intravital microscopy, RBC velocity, vessel diameter, functional capillary perfusion, and leukocyte–endothelial interactions were noted. Results After blood withdrawal, changes in RBC velocity, vessel diameter, functional capillary perfusion, and number of activated leukocytes were observed in both groups, but these changes were more significant in stored blood compared with fresh blood (P ≤.05). Conclusions Further work is needed to validate these findings, but these preliminary data suggest that stored blood may have a deleterious effect on the microcirculation.