Effect of washing units of canine red blood cells on storage lesions

Background In humans, washing stored blood products before transfusion reduces storage lesions and incidence of transfusion reactions, but the effectiveness of washing canine blood is unknown. Objectives The objective was to determine if manually washing units of stored blood would reduce storage lesions without adversely affecting erythrocytes. We hypothesized that washing stored units would reduce concentrations of storage lesions and cause minimal erythrocyte damage. Animals Eight healthy research dogs. Methods Repeated measure cohort study. Units of whole blood were stored for 28 days and washed 3 times with 0.9% NaCl. Blood samples were collected before and after storage, after each wash, and after being held at a simulated transfusion temperature. Variables measured included CBC variables, blood gas analysis, erythrocyte morphology, mean corpuscular fragility (MCF), and eicosanoid concentrations. A Friedman's test was used to evaluate changes in variables (P < .05 was considered significant). Results After the first wash, compared to values after storage, there was a significant decrease in potassium (4.3 mmol/L [4.0-4.7] to 1.2 mmol/L [1-1.6]; P < .0001, median [range]), lactate (1.45 mmol/L [1.07-1.79] to 0.69 mmol/L [0.39-0.93]; P = .002), and partial pressure carbon dioxide (102 mm Hg [80.2-119.2] to 33.7 mm Hg [24.5-44.5]; P < .0001), and increase in MCV (69.3 fL [65.7-72.3] to 74 fL [69.6-79.5]; P = .0003), and MCF (0.444 fL [0.279-0.527] to 0.491 fL [0.43-0.616]; P = .0006). Conclusions and Clinical Importance A single wash of stored whole blood significantly reduces most extracellular storage lesions, and additional washing might cause hemolysis.