All You Need to Know About Veterinary Blood Transfusions.

All You Need to Know About Veterinary Blood Transfusions.The decision to clinically transfuse a patient with blood products depends on several factors, including: 1)Availability of blood products. 2)Stability of the patient. 3)Chronicity of anemia. 4)Clinical signs of the patient If a patient is demonstrating signs of hemorrhagic shock such as pallor, tachycardia, tachypnea, snappy or thread pulses and decreased mentation, it likely needs a blood transfusion. But wait! Before reaching immediately for that unit of blood, reach for a bag of crystalloids first. Why? In general, most patients requiring a blood transfusion often have concurrent interstitial fluid loss and could benefit from IV fluid therapy. A hemorrhagic shock patient example: Start with a 20 mL/kg IV crystalloid bolus over 20 minutes, followed by patient reassessment. If signs consistent with hemorrhagic shock are still apparent, administer a second bolus (20 mL/kg crystalloids IV), followed by 5 mL/kg smaller aliquots of a colloid (eg, Hetastarch) if the patient fails to respond to crystalloids. If the patient still fails to respond, a blood product is warranted, regardless of what the PCV may be. In human medicine, the transfusion trigger is a hematocrit (HCT) of 25%, whereas in veterinary medicine it is approximately 20%. However, push this to the back of your brain, as some patients need a transfusion regardless of what the PCV is. Take, for example, that classic traumatic hemoabdomen patient. At presentation, the PCV may only be 30%, but they may have catastrophic bleeding, requiring multiple transfusions. To the contrary, a cat with FeLV may present with a PCV of 10%, only to find out that—because of the chronicity—this patient is hemodynamically stable (ie, it doesn’t need an emergency transfusion). Before transfusing, patients should ideally undergo blood-typing or cross-matching (depending on previous transfusions, history of pregnancy, or if there is risk for transfusion reaction). In dogs, if the disease process precludes testing (eg, immune-mediated hemolytic anemia, catastrophic bleed), a universal donor (DEA 1.1 negative or A-) should be used.However, dogs can receive a first time transfusion safely without being typed or cross-matched. Keep in mind that if it’s the dog’s first transfusion, a transfusion reaction is not anticipated, as antibodies haven’t formed yet (which typically take 3-7 days to develop). It’s the second transfusion that we worry about for transfusion reactions in dogs. Cats can die if they get the wrong type of blood. There is no universal blood donor for cats. As cats have natural alloantibodies, all cats should always be blood typed or cross-matched prior to transfusion, due to risk for fatal blood transfusion reactions. As little as 1 mL of A blood to a B cat can be fatal (Just as B students may hate A students, B blood hates A blood!). There’s no universal donor in cats. The dosage for ANY blood product is 10-20 mL/kg. Owners should be made aware that their pet has received transfusions, and should inform future veterinarians or caregivers in order to prevent reaction to second transfusions. Antibodies against a transfusion take 3 to 7 days to develop, so the use of cross matching should be implemented when multiple transfusions may occur during prolonged hospitalization. The use of blood typing cards may not beneficial once the patient has been transfused, as it’s testing for antigen.