Biochemical and hematologic changes in whole blood from Brazilian horses stored in citrate–phosphate–dextrose–adenine pouches for up to 28 days

Background Anaerobic cellular metabolism causes a series of structural and physiologic changes during storage that could compromise post‐transfusion viability, reducing the safety of using blood stored for an extended period. Objective We aimed to follow the biochemical and hematologic alterations of equine blood stored in plastic bags containing citrate–phosphate–dextrose–adenine (CPDA‐1) for up to 28 days. Methods Whole blood samples (450 mL) were collected from 20 Brazilian Saddle horses into CPDA‐1 pouches and stored between 2°C and 6°C in a blood bank. On days 0, 7, 14, 21, and 28 of storage, blood samples were taken and submitted for biochemical (sodium [Na+], potassium [K+], glucose, and lactate) and hematologic (hemoglobin [Hb], hematocrit [HCT], mean corpuscular volume [MCV], percent hemolysis [% hemolysis]) analyses. Results The only time the blood pH levels dipped below 7 was after D21 of storage, and the levels were significantly lower than those on the first storage day (D0). Potassium concentrations showed significant increases from D7 and then remained increased throughout the experimental period. Chloride and lactate concentrations revealed a significantly increased trend from D7 that was maintained over time. Mean corpuscular volumes increased significantly on D7 and D14 and, thereafter, remained stable. The mean % hemolysis increased on D28, which was significantly higher than D0. No bacterial growth was found in any pouch after 28 days of storage. Conclusions Significant and gradual biochemical changes were observed in equine whole blood during prolonged storage. These changes could compromise the clinical conditions of patients requiring transfusion. In vivo studies are needed to evaluate the effects as well as survival rates and efficacy of transfused red blood cells in recipients.