Background Acute normovolaemic haemodilution (ANH), as a blood-conservation technique, avoids the need for allogeneic blood transfusions. The historic practice of cold-storing type-O whole blood (WB) in military fields popularised the transfusion of refrigerated WB to treat acute bleeding. In this study, we compared the effects of room temperature (RT) and refrigeration up to 24 hours on the coagulation properties of WB for ANH. Materials and methods Each WB sample, collected from 12 male volunteers, was divided into two parts, one stored at RT and the other refrigerated for 24 hours. Complete blood counts (CBC), blood gas levels, and coagulation profiles were measured, and rotational thromboelastometry (ROTEM) measurements were performed at the initial collection time point (baseline) and at 6, 12, and 24 hours after initial collection. Results The preservation of platelet aggregation response induced by arachidonic acid and adenosine diphosphate was better in cold-stored WB compared to that in RT-stored WB. The platelet aggregation response induced by thrombin receptor-activating peptide 6 was significantly decreased in all samples after 24 hours of storage when compared with that at baseline. The lactate levels in WB stored at RT increased significantly after 6 hours of storage compared to that of cold-stored samples. There were no significant differences in CBC, coagulation parameters, and ROTEM variables between the cold-stored and RT-stored WB samples. Conclusion WB for ANH stored in the refrigerator showed better metabolic characteristics after 6 hours of storage and better aggregation response after 12 hours of storage than WB stored at RT.

Background: Acute normovolemic hemodilution (ANH), as a blood-conservation technique, avoids the need for allogeneic blood transfusions. The historic practice of cold-storing type-O whole blood (WB) in military fields popularized the transfusion of refrigerated WB to treat acute bleeding in surgical/trauma patients. In this study, we compared the effects of room temperature (RT) and refrigeration up to 24 hours on the coagulation properties of WB for ANH.Methods: Each WB sample, collected from 12 male volunteers, in citrate-phosphate-dextrose adenine solution was divided into two parts, which were stored at RT (20-24℃) and refrigerated (1-6℃) for 24 hours, respectively.Complete blood counts (CBC), mean platelet volume, and blood gas and fibrinogen levels were measured, and rotational thromboelastometry (ROTEM) measurements, including aggregation response, were performed at the initial collection time point (baseline) and at 6, 12, and 24 hours after initial collection.Results: The preservation of platelet aggregation response induced by arachidonic acid and adenosine diphosphate was better in cold-stored WB compared to that in RT-stored WB, which significantly decreased after 12 hours of storage when compared with baseline. The platelet aggregation response induced by thrombin receptor-activating peptide 6 was significantly decreased in all samples after 24 hours of storage when compared with that at baseline. Although pH levels were within acceptable limits for all samples, the glycolytic metabolism of WB stored at RT was accelerated, leading to a significant increase in lactate levels after 6 hours of storage compared to that of cold-stored samples. There were no significant differences in CBC, coagulation profiles, mean platelet volume, and ROTEM variables between the cold-stored and RT-stored WB samples.Conclusions: WB for ANH stored in the refrigerator showed better metabolic characteristics after 6 hours of storage and better aggregation response after 12 hours of storage than WB stored at RT. Considering the safety of refrigerated products in terms of reducing bacterial growth, these data suggest that cold-stored WB may improve outcomes in patients with acute bleeding.