Whole blood storage duration alters fibrinogen levels and thrombin formation.

INTRODUCTION: Whole blood resuscitation for hemorrhagic shock in trauma represents an opportunity to correct coagulopathy in trauma while also supplying red blood cells. The production of microvesicles in stored whole blood and their effect on its hemostatic parameters have not been described in previous literature. We hypothesized that microvesicles in aged stored whole blood are procoagulant and increase thrombin production via phosphatidylserine. METHODS: Whole blood was obtained from male C57BL/6 male mice and stored in anticoagulant solution for up to 10 days. At intervals, stored whole blood underwent examination with rotational thromboelastography, and platelet-poor plasma was prepared for analysis of thrombin generation. Microvesicles were prepared from 10-day-old whole blood aliquots and added to fresh whole blood or platelet-poor plasma to assess changes in coagulation and thrombin generation. Microvesicles were treated with recombinant mouse lactadherin prior to addition to plasma to inhibit phosphatidylserine's role in thrombin generation. RESULTS: Aged murine whole blood had decreased fibrin clot formation compared with fresh samples with decreased plasma fibrinogen levels. Thrombin generation in plasma from aged blood increased over time of storage. The addition of microvesicles to fresh plasma resulted in increased thrombin generation compared with controls. When phosphatidylserine on microvesicles was blocked with lactadherin, there was no difference in the endogenous thrombin potential, but the generation of thrombin was blunted with lower peak thrombin levels. CONCLUSION: Cold storage of murine whole blood results in decreased fibrinogen levels and fibrin clot formation. Aged whole blood demonstrates increased thrombin generation, and this is due in part to microvesicle production in stored whole blood. One mechanism by which microvesicles are procoagulant is by phosphatidylserine expression on their membranes.

Age above all: The impact of storage duration in mice resuscitated with whole blood or packed red blood cells and plasma in a hemorrhagic shock model.

BACKGROUND: The use of whole blood compared with a balanced ratio of components in trauma resuscitation remains an area of ongoing investigation. One factor that may affect outcomes is the age of the blood product transfused. We used a murine model of blood banking and hemorrhagic shock resuscitation to compare the effect of storage duration in whole blood and packed red blood cells on the recipient inflammatory response. METHODS: Murine whole blood or packed red blood cells were evaluated for the red blood cells storage lesion up to 14 days. Mice underwent hemorrhagic shock followed by resuscitation with whole blood or packed red blood cells combined with equal volume of thawed plasma (1:1) stored for 1, 7, or 14 days. Serum and lung cytokine/chemokine levels were measured and leukocyte infiltration determined via immunohistochemistry. RESULTS: Both whole blood and packed red blood cells develop a blood storage lesion. Four hours after resuscitation, mice resuscitated with either day 14 whole blood or 1:1 demonstrated increased inflammatory cytokines and chemokines with similar findings within lung tissue compared with mice resuscitated with whole blood and 1:1 products stored for 1 or 7 days. CONCLUSIONS: Resuscitation with murine packed red blood cells or whole blood stored for 14 days produces a pronounced recipient inflammatory response compared with those units stored for lesser durations. Given the shorter storage duration of human whole blood to packed RBCs, resuscitation with whole blood within current storage limits may represent an advantageous resuscitation strategy compared with older packed red blood cells.