Serial oxygen equilibrium and kinetic measurements during RBC storage

Objectives: To contribute to the understanding of the biochemical changes associated with the RBC storage lesion. Aim: To investigate changes in O-2 equilibrium and on/off kinetic rates during routine cold storage. Background: As RBCs are stored between 1 and 6 degrees C numerous biochemical changes occur within the RBCs, including changes in the properties of the haemoglobin itself. This study serially analysed for the first time the O-2 equilibrium and on/off kinetic rates across the RBC membrane during routine storage. Methods/Materials: The oxygen binding (k(on)) and offloading (k(off)) constants were measured in fresh RBCs and then in AS-5-preserved RBCs at weekly intervals, along with oxygen equilibrium curves (OECs), 2,3-Diphosphoglycerate (2,3-DPG), p50 and the Hill number (n). Results: The k(on) increased slightly as the 2,3-DPG and p50 decreased during storage, whereas the k(off) remained largely unchanged. The OECs demonstrated the expected increase in O-2 affinity, whereas the Hill number was unchanged during storage. Conclusion: In spite of the biochemical, structural and functional changes associated with the storage of RBCs, their in vitro interactions with oxygen were largely preserved through 42 days of storage.