Retrospective Evaluation of Blood Product Transfusion Outcomes and Risk Factors for Transfusion Reactions in Dogs at a Veterinary Teaching Hospital with an Established Blood Bank: 137 Dogs (2018-2022).

Abstract

Objective: To evaluate the outcome of blood transfusions in dogs and identify the incidence of and risk factors associated with transfusion reactions (TRs) classified according to the Association of Veterinary Hematology and Transfusion Medicine (AVHTM) consensus.

Design: Retrospective cross-sectional study with cohort analysis, January 2018-March 2022.

Setting: Veterinary teaching hospital with a well-established blood bank.

Animals: One hundred thirty-seven dogs.

Interventions: None.

Measurements and main results: Medical records and transfusion logs of dogs receiving blood transfusions were reviewed. Transfusion outcomes and TRs were assessed according to predefined definitions, TRs as classified by the AVHTM consensus. Two hundred seventeen transfused units (TUs) and 190 transfusion events were documented. Transfusion outcome was successful for 29.5%, moderately improved for 23.7%, and not improved for 9.4% transfusions. The definitions proved especially informative when applied to indications for which a large number of patients received blood products, showing that transfusions generally improved clinical and laboratory parameters in anemia, hypoalbuminemia, and hemostatic dysfunction associated with angiostrongylosis. TRs occurred in 12.4% patients, the most common being an acute hemolytic TR (13/21 of all TRs [61.9%]). TR imputability (cause) was definite for 3 of 21 (14.2%), probable for 16 (76.2%), and possible for 2 (9.6%) TUs. TRs were more common with red blood cell (RBC)-containing products (p ≤ 0.0001) and in dogs with immune-mediated hemolytic anemia (IMHA) (p = 0.002). No associations were found between TRs and administered dose (p = 0.8), transfusion rate (p = 0.053), packed RBC age (p = 0.3), or patient transfusion history (p = 0.3). There were more successful outcomes for transfusions without a TR (p = 0.008; odds ratio: 6.3, 95% confidence interval: 1.6-28.6).

Conclusions: Using established outcome definitions, outcome was successful in 29.5%. TRs were more common when RBC-containing products were administered and in dogs with IMHA.