RESUMEN
OBJECTIVES: To describe the biochemical changes - also known as the storage lesion - that occur in canine packed red blood cells during ex vivo storage. MATERIALS AND METHODS: Ten 125-mL units of non-leuco-reduced packed red blood cells in citrate phosphate dextrose adenine were obtained from a commercial blood bank within 24 hours of donation. Samples were aseptically collected on days 1, 4, 7, 14, 28, 35 and 42 for measurement of sodium, potassium, chloride, lactate, glucose, pH and ammonia concentrations. All units were cultured on day 42. Friedman's repeated measures test with Dunn's multiple comparison test was used for non-parametric data. A repeated-measures analysis of variance with Tukey's multiple comparison test was used for parametric data. Alpha was set to 0·05. RESULTS: All analytes changed significantly during storage. The mean ammonia on day 1 (58·14 g/dL) was significantly lower (P<0·05) than those on days 28 (1266 g/dL), 35 (1668 g/dL) and 42 (1860 g/dL). A significant increase in median lactate concentration over time was also observed, with day 1 (4·385 mmol/L) being significantly less (P<0·05) than days 14 (19·82 mmol/L), 21 (22·81 mmol/L), 35 (20·31 mmol/L) and 42 (20·81 mmol/L). Median pH was significantly decreased after day 7. All bacterial cultures were negative. CLINICAL SIGNIFICANCE: Many biochemical alterations occur in stored canine packed red blood cells, although further studies are required to determine their clinical importance.