Randomized study of washing 40- to 42-day-stored red blood cells.

Bennett-Guerrero E, Kirby BS, Zhu H, Herman AE, Bandarenko N, McMahon TJ
Transfusion 2014;54:2544-2552.
NATA Rating :
Review by : G. Inghilleri
NATA Review

This preliminary study compared the effectiveness of two different systems for RBC washing, a point-of-care device (Haemonetics Cell Saver Elite autotransfusion system) and a transfusion-service-based device (Terumo COBE 2991 cell processor), in reducing the content of potentially harmful by-products of RBC storage (free haemoglobin and RBC microparticles) in longer-stored (40-42 days) RBC units. It also evaluated the effect of washing on the vulnerability of RBCs to mechanical stress.

The topic is of interest because washing has been reported in recent years as an effective method to limit the negative impact on clinical outcome caused by the transfusion of “old” blood. In this perspective, the evaluation of the performance of a point-of-care device for cell washing is certainly of great interest as this type of systems can offer, in comparison with transfusion-service-based devices, consistent logistical advantages, and could allow for more timely and efficient washing of RBC units.

Altogether, the results of the study, carried out on a total of 40 units, cast consistent doubts on the effectiveness of cell washing in improving the quality of older-stored RBC units, in particular for the point-of-care system. Indeed, although both devices recovered a high percentage of RBCs and efficiently removed extracellular potassium, washing with the point-of-care device resulted in significant increases in cell-free haemoglobin, percent haemolysis, and RBC microparticle production, whereas washing with the COBE 2991 did not lead to significant changes. No significant increase in RBC fragility due to washing was observed with either of the two systems.

Unlike other studies demonstrating a potential benefit of RBC washing before transfusion (Cholette JM et al. Pediatr Crit Care Med 2012;13:290-9), this study did not evaluate any “in vivo” parameters, and definitive conclusions cannot be made. However, in view of the results obtained, it seems reasonable to agree with the authors’ conclusion that more data are needed before washing of stored RBCs can be routinely recommended for transfusion.

– Giovanni Inghilleri

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