Acid-base and electrolyte changes in dogs after packed red blood cell transfusion

Background: Packed RBC (pRBC) transfusions are often necessary to enhance organ perfusion and tissue oxygenation in cases of severe anemia. Objectives: We aimed to describe changes in acid–base and biochemical parameters in dogs after transfusion of pRBC and potential effects on the outcome. Methods: The prospective observational study included anemic dogs requiring pRBC transfusions. Venous blood gas and electrolytes were measured pre-transfusion and repeated within 1 h post-transfusion. Signalment, pre-existing conditions and underlying disease(s), number of days spent of hospitalization, the quantity of transfused pRBC units, and the outcome were also recorded. Associations between analytical values and all other parameters before and after transfusion were assessed using the Wilcoxon test. A generalized linear model was generated for each of the blood gas parameters post-transfusion, including the pre-transfusion values and the characteristics of the animal as fixed effects. The effect of the blood gas parameters on the mortality and hospitalization length was assessed using logistic regression and generalized linear models, respectively. Results: Twenty-six dogs with different causes of anemia were included in the study, with dogs remaining hospitalized for a median of 3 days (range: 0–11). Pre-transfusion heart rate, respiratory rate, Angap, base excess, and lactate were higher than post-transfusion values. Post-transfusion results showed an increase in hematocrit, hemoglobin, HCO ₃-, PCO ₂, tCO ₂, and chloride. Pre-transfusion hypophosphatemia and receiving an increased volume of transfused pRBC were associated with a longer hospital stay, while higher pre-transfusion lactate values were associated with higher mortality. Conclusions: pRBC transfusion in anemic dogs was associated with an improvement in perfusion and acid–base parameters. Pre-transfusion lactate may be an indicator of mortality in dogs.