Background: Red blood cells (RBC) are subject to oxidative stress by reactive oxygen species during refrigerated storage. Near-complete removal of oxygen from red cells during storage should eliminate this contributor to the red cell 'storage lesion'. The in vitro effects of storing red cells under oxygen-depleted conditions for extended periods were investigated, and these were correlated with the observed recoveries after reinfusion.
Study design and methods: Units of red cells, obtained after 'soft spin', were placed in a double volume of AS-3 additive solution and subdivided. Oxygen in the test units was depleted by repeated exposure to Ar gas (to O(2) saturation < 4%), and units were stored in anaerobic canisters for up to 15 weeks. Samples were taken weekly to monitor adenosine triphosphate (ATP), 2,3-diphosphoglycerate (2,3-DPG), cell-free haemoglobin, and vesicle production. In a parallel experiment, six units of red cells was depleted of oxygen in a similar manner, stored for 8, 9 and 10 weeks, and reinfused autologously to determine the 24 h post-transfusion recovery via (51)Cr/(99m)Tc radiolabelling. A similar study was also carried out using EAS61 additive solution, which by itself, had shown the ability to support 9-week storage, comparing biochemical profiles and in vivo recovery after aerobic vs. anaerobic storage.
Results: Oxygen-depleted AS-3 units had significantly elevated ATP levels compared to controls. They also had significantly lower cell free haemoglobin and vesicle production when RBCs were stored for more than 9 weeks. An average of over 75% post-transfusion survival was observed after 9 weeks of anaerobic storage with less than 0.43% haemolysis. However, no further extension of storage was achieved with EAS61 additive.
Conclusion: Anaerobic conditions permit acceptable 9-week storage of RBCs using double-volume AS-3 additive solution. It did not synergize with the alkaline, 9-week additive, EAS61, to further lengthen the acceptable storage time. These studies indicate that anaerobic storage may allow reduction in the effect of the storage lesion, but suggest that other factors contribute to limitations of RBC storage as well.