Washing of Stored Red Blood Cells by an Autotransfusion Device Before Transfusion

Background: The use of an autotransfusion device to wash blood of the incision site is increasing. After washing, this blood is retransfused without side effects caused by activated plasma factors and cell release products. This procedure could be extended to washing of donor blood, which may be particularly useful for red blood cells (RBCs) stored for more than 4 weeks that contain high concentrations of free haemoglobin, potassium, lactate and other metabolites. It is not known whether stored RBCs can withstand the cell washing procedure with the use of an autotransfusion device, while keeping their primary functions intact. The objective of this study was to determine the quality of RBCs, after cell washing in comparison to untreated RBCs.

Materials and Methods: RBCs were studied in terms of integrity (free haemoglobin), stored energy (2,3-diphosphoglycerate, adenosine triphosphate), metabolites (lactate, potassium) and physical characteristics (osmotic resistance, aggregability, deformability).

Results: After washing, free lactate and potassium were significantly reduced as compared to the levels before washing. The osmotic resistance of RBCs slightly improved, whereas aggregation capacity reduced after washing. Fifteen per cent of haemoglobin was lost during washing. The deformability and free haemoglobin levels remained unchanged.

Conclusion: Washing stored blood before transfusion may be of benefit, because the waste products are effectively removed from the stored RBC.