Red Blood Cell Transfusions in Cats

Previous studies have demonstrated that canine red blood cell (RBC) transfusions delivered via mechanical pump methods, especially syringe and aggregate filter methods, cause increased destruction of  transfused RBCs. It is not known if this increased destruction occurs during feline RBC transfusions. Feline RBCs are smaller than canine RBCs and have a greater increase in stiffness during hypoxic conditions, thus they may behave differently from canine RBCs under the same transfusion conditions.

This prospective study analyzed autologous feline RBC transfusions in 6 cats. Biotin-labeling and flow cytometry were used to evaluate the effect of the transfusion procedure on short-term survival and circulating half-life of transfused RBCs. RBCs were transfused using either gravity or mechanical pump using a 20-mL syringe and 18-µm microaggregate filter. Following the transfusion, whole blood samples from the cats were analyzed to assess circulating half-life of transfused cells. Autologous transfusion of feline RBCs using the syringe and aggregate filter method did not significantly impact the short- or long-term survival of feline RBCs compared with the gravity method.

Commentary

Autologous transfusion in healthy cats through a microaggregate filter within 12 hours of collection resulted in good RBC survival that was comparable to normal feline RBC survival. In a similar study of healthy dogs, 24-hour canine RBC survival was much shorter (<24 hours) in the microaggregate group.¹ The canine study, however, did not report how soon the blood was reinfused after collection and processing. The difference may be because of smaller volumes of blood being collected in the feline study and the smaller size of feline RBCs. This may allow feline RBCs to pass through the filter with less trauma.—Elke Rudloff, DVM, DACVECC