Exchange transfusion therapy and its effects on real‐time microcirculation in pediatric sickle cell anemia patients

Abstract

The goal of exchange transfusion therapy is to ameliorate vasoocclusion and improve tissue perfusion by removing sickled red blood cells and introducing normal red blood cells. Using computer‐assisted intravital microscopy, pre‐transfusion and post‐transfusion microvascular characteristics were analyzed and compared. In this study, the bulbar conjunctiva exhibited a “blanched” avascular appearance in all 6 pediatric sickle cell anemia patients before transfusion, indicative of tissue hypoperfusion and ischemia. Immediately after transfusion, substantial improvement in vascularization and tissue perfusion resulted. In addition, a decrease in red cell velocity was observed. These observations provide evidence that exchange transfusion therapy is beneficial in ameliorating vasoocclusion and improving tissue perfusion. However, with the paradoxical post‐transfusion decrease in red cell velocity presumably due to induced hyperviscosity from the large transfusion volume, blood flow is still impaired. This decreased velocity may thwart efforts to improve oxygen delivery through transfusion and may, to some extent, promote vasoocclusion instead.