Blood Loss and Transfusions Flashcards
What is a blood transfusion?
Transferring blood or blood based products from one individual to another of the same species
What is the purpose of a transfusion?
- Increase Hb content of blood
- Increase circulating volume
- Increase plasma albumin content
- Provide coagulation factors
- Provide functional platelets
What is the percentage of blood loss that is fatal?
50% total volume
Is losing 50% of hemoglobin fatal?
May not be but depends on the individual
What are the types of blood products?
- Fresh whole blood
- Packed red cells
- Fresh frozen plasma
- Cryoprecipitate
- Platelet rich plasma
What PCV does it have to be to be considered whole blood versus packed red cells?
Whole blood- 40%
Packed red cells- 70%
How do you increase Hb content of blood if TP is
Fresh whole blood
How do you increase Hb content of blood if TP is >3.5?
Packed red cells
How long do RBCs survive normally?
60-120 days
Less if there is an immune reaction
What is the percentage loss needed to require transfusions in an acutely bleeding patient?
> 20% total volume
>10-15% if perioperative
Transfusions are requred at which PCV values for:
Acute anemia, chronic anemia, anemia with anesthesia
Acute anemia-
Are clinical signs or values more important when considering transfusions?
Clinical signs
Is a higher or lower Hb content needed in cases of organ dysfunction?
Higher!
What are the clinical signs of blood loss (acute or chronic)?
- Pale MMs
- Elevated HR
- Low BP
- Weak pulses
- Blood in surgical sponges or containers
Will acute blood loss always result in changes in PCV and TP?
No! Not reliable
How much blood does a standard surgical sponge contain?
~5mL
How is blood loss calculated from fluid in canisters?
mL= (PVC fluid x Vol fluid)/ Preop PCV
How much blood volume should be given in acute blood loss?
The same amount that was lost
What is the general rule for increasing PCV?
2mL whole blood/kg raises PCV by 1%
What is the calculation for volume of blood to be transfused?
([PCVreq-PCVhave]xblood volume)/PCVdonor
What are the empirical dosages for transfusions in dogs and cats?
10-40mL/kg Dogs
5-20 mL/kg Cats
What dosage should be started to test?
0.25mL/kg for 30 min to test reaction then it can be increased
When should a transfusion be completed by?
Within 4 hours
Can blood be mixed with LRS?
No- blood will clot due to Ca content
Should a separate IV port be used for blood products?
Yes
Can blood products be refrozen after they’ve been thawed?
NO- use it or lose it
Which blood product is inappropriate for increasing albumin content?
FFP
Which blood product should be used to increase albumin content?
Concentrated albumin
What is the disadvantage to using 5% human albumin?
Allergic reactions are commmon
What is the diadvantage to using canine albumin powder?
Very expensive
What products can be used to provide coagulation factors?
Cryoprecipitate (best option)
Fresh whole blood
Fresh plasma
FFP
Why should older products not be used to proved coagulation factors?
Certain more unstable coag factors will be lost
What is a concern when giving plasma (fresh or frozen)?
Allergic reaction or immunity against blood group antigens
What is the best blood product to provide functional platelets?
Fresh whole blood
Why should whole blood be stored/administered in plastic if you are using it for functional platelet transfusion?
Platelets will adhere to glass
Fresh whole blood should be given within ____hrs after collecting for functional platelet transfusions.
8 hours
Why wouldn’t platelet rich plasma be given in a functional platelet transfusion?
Very difficult to obtain in vet med
What are some donor selection criteria?
- Free of blood born diseases
- Up to date on vaccines
- Good physical condition
- Young adult
- Medium to large size
- Castrated males or nulliparous females preferred
What are some complications of transfusions?
- Blood type incompatibility
- Allergic reaction
- Immune reaction
What are some side effects of transfusions?
- Circulation overload
- Transfusion related lung injury
- Citrate induced hypocalcemia
- Sepsis
- Infectious disease transmission
When are transfusions usually reserved for?
When it is necessary to save a life
What is seen in an acute blood type incompatibility?
Hemolysis and agglutination
Life threatening!
What is seen in slow blood type incompatibility?
Delayed or slow hemolysis with decreased lifespan of RBCs
What are the clinical signs of an acute transfusion reaction?
- Increased HR/RR, decreased BP, dyspnea
- Vomiting, tremors, wheals, urticaria, fever, pain
- Hemolysis, Hb-uria, renal failure, DIC, CV collapse
Will signs of acute transfusions reactions be increased or decreased while under anesthesia?
Decreased! Must observe closely
What is the treatment for an acute transfusion reaction?
STOP!
Treat everything else symptomatically
Which two blood types in dogs have strong antigenic responses?
DEA 1.1 and 1.2
Are there naturally occurring antibodies in dogs against blood types?
No, this means that the first incompatible transfusion is usually fine but the second can be fatal
What are the three feline blood groups and which are most common?
A- most common
B- more rare but common in certain breeds
AB- typically pure breed cats
Do cats have naturally occurring blood antigen antibodies?
Yes! This means blood typing is compulsory
What is the other blood system in cats and do we care?
Mik, and no
What are the most antigenic equine blood groups?
Aa and Qa
Is blood typing and cross matching easy on equines?
No
What kinds of horses are most likely to have antibodies against blood types?
Mares that have fouled- neonatal isoerythrolysis concerns
What kind of horses are the best for donors?
Geldings or nulliparous mares of the same breed
What is cross-matching and what is the reaction observed?
Determines serological compatibility, look for agglutination
agglutination is a positive reaction- do not use!
What is the difference between a major and minor cross match?
Major- donor RBC + recipient plamsa
Minor- recipient RBC + donor plasma
What is oxyglobin?
Chemically stabilized bovine hemoglobin
What is oxyglobin used for?
Treat anemia in dogs
What is oxyglobin’s duration of effect?
Min 24 hours
What are some concerns of using oxyglobin?
May cause circulatory overload, allergic reaction on repeated dosages, and give the appearance of jaundice
