Feline transfusion medicine: current Australian blood banking and transfusion practices and the effect of storage lesion

Abstract

Blood transfusions are an essential and potentially lifesaving intervention in feline emergency and critical care medicine. While recent research has expanded understanding of species-specific differences in haemorheology and transfusion medicine, there are still significant and clinically important deficits in the evidence-based literature. Objectives 1. To describe how Australian emergency and specialty referral hospitals source feline blood products, approach collecting blood donations and to identify and characterise feline blood storage practices. 2. To determine whether passage through an 18 μm microaggregate filter damages feline RBCs as indicated by increased haemolysis percentage, mean osmotic fragility or haematological derangements and if these effects are compounded in blood that has been stored for 35 days. 3. To determine if a commercially available open blood collection system carries risk of bacterial contamination. Methods: The first objective was investigated via an electronic survey distributed to Australian small animal emergency and/or referral hospitals. The second and third objectives were investigated with an experimental study using nine cats recruited for a single blood donation using an open collection system. A simulated transfusion using a syringe pump and microaggregate filter was performed over two hours with half the blood on the day of donation and the other half after 35 days storage. Results and conclusions: While most hospitals performed feline blood transfusions, few stored feline blood, and the means of blood collection, storage times and subsequent processing differed across sites. Fresh RBCs exhibited no in vitro evidence of injury following passage through an 18 μm microaggregate filter. Increased mean corpuscular haemoglobin was observed in the stored blood and may represent haemolysis induced by the filter. All other changes can be explained by storage lesion rather than filter passage. All blood units cultured negative.