Retrospective evaluation of the indications, safety and effects of fresh frozen plasma transfusions in 36 cats (2014–2018)

Mansi ET, Waldrop JE, Davidow EB. Retrospective evaluation of the indications, safety and effects of fresh frozen plasma transfusions in 36 cats (2014-2018). J Feline Med Surg [Internet]. 2019 Oct 2

Transfusion of blood products is increasingly common in veterinary medicine for a variety of indications. The use of blood components has reduced the risks of transfusion reactions compared to whole blood, however risks are still present. Fresh-Frozen Plasma (FFP) is used to manage coagulopathies, low albumin, and occasionally for other indications (such as pancreatitis), but it may be overprescribed and in human medicine is commonly replaced with single factor concentrates. The purpose of this study was to determine the efficacy and rate of transfusion reactions in cats receiving FFP.

 The study was designed as a retrospective observational study investigating the rate of transfusion reactions, changes in coagulation parameters, and clinical outcomes in cats receiving transfusions of fresh frozen plasma at two emergency facilities over a 4 year period.

All cats receiving FFP transfusions in the study period were eligible for enrollment. Signalment and demographic parameters, reason for transfusion, vital signs during transfusion, PCV/TP/PT/aPTT before and after transfusion, survival to discharge, and 7 day outcome were recorded. Each administration of a unit of FFP was considered a separate transfusion. Some cats received packed cells or whole blood along with FFP. All cats received blood of the same A/B/AB type. Major crossmatches were performed but minor cross matches were not. All donors were community cats screened according to ACVIM protocols.

Transfusion protocols and monitoring were performed according to generally accepted practices, and transfusion reactions defined by previous consensus. Full details can be found in the manuscript.

36 cats received 54 FFP transfusions (one cat with hemophilia was transfused on two occasions for different reasons). Three reasons for FFP transfusion were notes: coagulopathy prior to invasive procedure (19 cats), coagulopathy without invasive procedures (16 cats), and hypoalbuminemia (2 cats). Causes of transfusion included hepatopathy, septic abdomen, neoplasia, anticoagulant rodenticide, and DKA. 89% of cats were type A and 11% type B.

22 cats received a single transfusion (median volume 5.87mL/kg), 13 received two transfusions (median 9.4mL/kg), and 2 cases received three transfusions (median 10.63mL/kg). Overall median transfusion volume was 6.81mL/kg.

Paired coagulation testing was available in 20 cats before and after transfusion. Coagulation parameters improved in 18/20 cats. Median change in per unit plasma was  -27.5s PT and -80s aPTT.

8 of 36 cats (22%) had probably transfusion reactions, accounting for 14.8% of transfusions. Only one of the transfusions were discontinued by the attending clinician. Of the 8 likely reactions, 3 of the transfusions were FFP alone, while 5 also received pRBCs. No cats developed hemolysis, hypotension, or neurologic deficits. No cats died during the transfusion, however 3 died within 4 hours of termination of transfusion. These cats were all unstable and death was not thought to be associated with transfusion.

4 of the reactions were respiratory in nature (it is unclear if these were transfusion related acute lung injury or other etiology), 2 were febrile, and 2 were gastrointestinal in nature.

The authors concluded that FFP may be used in coagulopathic cats to decrease the PT and PTT. The risk of transfusion reactions in typed and cross matched cats is low.

The retrospective nature and small number of patients enrolled in this study are both limitations that may influence the validity of results. Further prospective work with a larger number of patients is indicated to support this data.

Based on the data in this study, the administration of 2-10mg/kg of FFP to cats is likely effective in treating coagulopathy and is associated with a low risk of adverse effects.

See Also

Wardrop KJ and Brooks M. Plasma products. In: Yagi K and Holowaychuk MK (eds). Manual of veterinary transfusion medicine and blood banking. Ames, IA: John Wiley & Sons, 2016, pp 43–54.

Castellanos I, Couto CG and Gray TL. Clinical use of blood products in cats: a retrospective study (1997–2000). J Vet Intern Med 2004; 18: 529–532.

Beer KS and Silverstein DC. Controversies in the use of fresh frozen plasma in critically ill small animal patients. J Vet Emerg Crit Care 2015; 25: 101–106.