Fresh Frozen Plasma (FFP) refers to the liquid component of anticoagulated blood that has been frozen within 8 hours of collection. It is used in medicine primarily as a treatment for coagulopathy or anticoagulant toxicity to replace clotting factors. It has also seen use to increase albumin levels (though it is very inefficient for this), to replace fluid volume in conjunction with pRBCs in cases of hemorrhage (though whole blood is also commonly used for this), or as a replacement fluid for techniques such as plasmapheresis. It may also be used in cases of pancreatitis, parvoviral enteritis, rattlesnake envenomation, and other situations, though these uses are more controversial. Possible risks of transfusion include immunologic reactions, acute lung injury, and circulatory overload. Though use-cases of FFP in human and canine medicine are described, there is a lack of knowledge in feline medicine.
The purpose of this study was to describe the use cases, doses, and rate of administration of FFP to cats, with secondary objectives of describing the response to therapy. It was designed as a retrospective observational study of cats presenting to a referral/emergency center over a 7-year period. Patients were excluded for incomplete medical records.
One hundred thirty patients were recorded as having received feline plasma, of which 9 were excluded, leaving 121 in the analysis. Seventy-one cats were male and 50 female, with a median age of 9.8 years. 88% of cats were blood type A, 2.5% B, 1.6% AB, and 7.4% untyped. Pretransfusion clotting times were available for 74% of cats, but post transfusion times only in 35%.
Multiple transfusions were given to 20 cats for a total for 51 transfusion events; 3 of these cats on separate visits, and one cat on 5 occasions (for a congenital factor deficiency). As such, 127 transfusion events were recorded.
The most common conditions in this population were liver disease, sepsis, and neoplasia. Indications for transfusion included: coagulopathy (84%); hemorrhage (35%); persistent hypotension (25%), and hypoalbuminemia (5%). Note that many cats had multiple indications for transfusion. All cats with hypotension as a primary indication had previously received a combination of crystalloids, synthetic colloids, vasopressors, and hydrocortisone. All cats with hypoalbuminemia were also coagulopathic or hypotensive. 33% of coagulopathic cats had concurrent hemorrhage.
61% of cats had improved coagulation times post transfusion, with odds of survival 2.4x greater if values improved. Cats with coagulopathy or hemorrhage were significantly more likely to survive than those with hypoproteinemia or hypotension. Systolic blood pressure significantly increased post transfusion, while respiratory rate decreased, and HCT and BG decreased (though not clinically significantly).
No difference was found in dose or transfusion reactions based on indication. Median dose was 6mL/kg over a mean of 4h transfusion time. Cats receiving multiple transfusions had a lower mean initial dose than single transfusions (4mL/kg). Dose did not correlate with survival, but was negatively associated with body weight.
Lower temperature, blood pressure, and heart rate were associated with mortality, likely as markers of disease severity. Interestingly, hemorrhage was associated with an increased chance of survival.
Seventeen transfusion reactions occurred. The only fatalities that occurred during or after transfusion were considered to be due to the disease process and not the transfusion. The most common reactions, in order, were hyperthermia, tachypnea, hypotension, and emesis.
Limitations to this study exist. The study is a single center retrospective, which may introduce geographic and institutional bias. Incomplete records and lack of full workup of all cats also hampered analysis. A controlled, prospective study would provide more information. Some of the data gathered here may be biased due to previous recommendations- i.e. the fact that cats received a lower dose than dogs/humans may be because of previous recommendations to transfuse a lower dose, and not because they required or could tolerate less.
Overall, the authors conclude that the use of plasma in cats is similar to that in dogs and humans, with coagulopathy/ hemorrhage the most common indication. Plasma appears effective in most cases as a treatment for coagulopathy, and may also be useful in increasing in blood pressure. Doses in cats are lower than those in other species. (MRK)