A Review of the Pathophysiology and Consequences of Red Cell Storage-Fresh Versus Stored Red Cells-Implication for Optimum Use of Scarce Allogenic Blood

About 90 million units of red blood are transfused worldwide yearly. Transfusion of red cell saves lives enabling complex haemorrhage prone surgeries and therapies to manage anaemia to be carried out. Challenges associated with the transfusion of allogenic blood including immunological and risk of transfusion transmissible infections. Red cells are stored at a temperature of 4 ± 2°C. At this storage temperature, it is ow possible to potentially store blood intended for transfusion for up to 42 days. However, due to red cell lesion-related challenges, stored red blood cells undergo a progressively degradation resulting in depletion of energy source to operate the physiological processes. This often affects the structural integrity of the red cell membrane, the deformability that allow it to pass through microcirculation to perfuse tissues and it fragility resulting in some level of haemolysis and the release of haemoglobin contained in its cytoplasm into the plasma. There had been an ongoing debate on whether it really matters in terms of optimum patient care what red cells transfusion a patient receives (fresh or older blood). Many have argued that the fresher the RBCs the better why others are of the opinion that there is no difference in patient outcomes between those transfused older and fresher RBCs. However, evidence seems to show that the transfusion of stored RBCs particularly those close to the end of the approved shelf life can potentially lead to morphologic changes that can potentially affect the ability of red cells to carry out the function of oxygen delivery. These changes include changes in cell shape from biconcave to spherical, increase in red cell adhesiveness to vascular endothelium, a decline in deformability and capillary flow, increased concentration of iron in the plasma due to release of free iron into the plasma due to haemolysis increasing the risk of nosocomial infections, thrombosis, vascular dysfunction, oxidative damage and associated challenge of organ failure, increased hospital stay and potential death. Transfusing fresher RBCs may benefit some patient cohorts, such as neonates, sickle cell disease, thalassaemic, septic and other severely ill patients particularly those in intensive care units while offering a limited or no benefit for the majority of other patients. Older RBCs might be given to certain patients’ groups, such AASCIT Journal of Medicine 2018; 4(2): 32-50 33 as those with trauma having a major haemorrhage and extensive surgical procedures requiring large amounts of RBCs. However, many can also potentially argue that these patients may benefit most from fresher RBCs. Implementing and maintaining any policy of fresher RBCs have cost implication and may be associated with a significantly higher rate of outdating. It may also require major operational changes to the current practice of collection, storage and transfusion that can potentially affect the optimum use of scarce allogeneic blood particularly in developing countries where blood is scarce and available stock is inadequate to manage the transfusion needs of patients. There is the urgent need for the development of more optimum storage solution that can reduce the red cell lesion related challenges associated with cold storage of RBC. There is need for the shelf life of red cells to be determined and strictly regulated based on evidence on the basis of large and pragmatic clinical trials on the vitro haemolysis and in vivo recovery and survival. This will help maximize the suboptimal allogeneic stock of donor blood particularly in developing countries where there is difficulty meeting the increasing demand and transfusion needs of a vast number of patients.