Whole blood [WB] transfusion is an effective therapy used to reduce the large number of preventable deaths from hemorrhagic trauma. The long-term objective of this project is to develop a modernized WB storage platform that reduces initial oxygen content and maintains an oxygen-managed environment during refrigerated storage in order to provide higher quality red blood cells (RBCs) for efficacious oxygen delivery and shock reversal, while maintaining bioequivalence in hemostatic and platelet (PLT) activity compared to conventionally prepared WB. To reduce waste and enable wide- spread adoption of WB, the proposed platform will include a novel WB additive solution, as well as a bag and an RBC additive solution to recover and store RBC for 6 weeks from expired WB, as the RBCs have a longer shelf life. Unlike the RBCs, PLTs contain mitochondria and rely on oxidative phosphorylation both in vivo and at room temperature during storage for their viability. PLT metabolism at 1-6°C is significantly reduced, and the cytochrome oxidase in mitochondria is known to have a very low Km. Unfortunately, the extensive preliminary in vitro data which has been collected to date does not provide a clear answer regarding the effects of stable low oxygen tension (~10-20mmHg) on PLT hemostatic function. The goal of this Phase 1 proposal is to obtain definitive data supporting the hypothesis that with its reduced metabolic demands, the hypoxic RBC storage condition will provide adequate O2 tension to sustain PLT’s hemostatic function, which would enable the project to proceed. The feasibility of this project will be critically tested in this Phase 1 study by making hypoxic WB using an existing hypoxic RBC processing system and tested in a small animal model study to compare the hemostatic function of conventionally and hypoxically stored WB. Additionally, an in vitro study examining status of activation and activatability of PLT under rejuvenated conditions mimicking the transfused state. If the milestone of Phase 1 is successfully reached, the development of both a novel hypoxic WB storage platform with a newly formulated additive solution for the WB collected in CPD and a RBC storage solution enabling a full 6-week shelf life for hypoxic RBC recovered from unused WB will begin. For both solutions, a successful metabolomics based high-throughput additive screening method, developed under separate SBIR Phase II grant for the screening novel hypoxic RBC additive solution, will be utilized.