THERAPEUTICS - Blood Transfusions Flashcards
What are the two main indicators for administering blood products?
Management of haemostatic disorders
Management of anaemia
What are the five commercially available blood products available for dogs?
Whole blood
Packed red blood cells (pRBCs)
Plasma (fresh frozen and frozen)
Cryoprecipitate
Platelet-rich plasma
How long can whole blood be stored for?
Whole blood can be stored for 28 days at 4°C
How long can packed red blood cells (pRBCs) be stored for?
Packed red blood cells (pRBCs) can be stored for 43 days at 4°C
When would it be appropriate to use packed red blood cells (pRBCs) over whole blood?
Use packed red blood cells (pRBC) to manage anaemia in normovolaemic patients, as if you use whole blood to manage anaemia in normovolaemic patients, there is a risk of fluid overload
How long can fresh frozen plasma be stored for?
Fresh frozen plasma can be stored for a year at -20°C
When would plasma be classified as frozen?
Plasma is classified as frozen if it has been stored at -20°C for over a year. Frozen plasma can be stored for 5 years
What are the indicators for administering fresh frozen/frozen plasma?
To manage haemostatic disorders
To manage hypoproteinaemia
What are the commercially available blood products available for cats?
Whole blood
What is the main risk of a blood transfusion?
Blood transfusion reactions
What are the two main classifications of blood transfusion reactions?
Immunologic blood transfusion reactions
Non-immunologic blood transfusion reactions
What are immunologic blood transfusion reactions?
Immunologic blood transfusion reactions are where there is an immune-mediated response against the transfused erythrocyte antigens
What are the two classifications of immunologic blood transfusion reactions?
Haemolytic
Non-haemolytic
What causes haemolytic blood transfusion reactions?
Haemolytic transfusion reactions are caused by the administration of incompatable or mismatched blood as the body can generate antibodies against the surface antigen of the transfused blood
What causes an acute haemolytic transfusion reaction?
An acute haemolytic transfusion reaction is caused by intravascular haemolysis of the transfused blood, which can result in disseminated intravascular coagulation (DIC), hypotension and death
What causes a delayed haemolytic transfusion reaction?
A delayed haemolytic transfusion reaction presents 2 to 21 days post transfusion due to extravascular haemolysis of the transfused blood, which will negate the benefits of the transfusion
What can be done to minimise the risk of haemolytic transfusion reactions?
Blood typing
Cross-matching
How are blood types determined?
Blood types are determined based on the inherited surface antigens present on the erythrocytes
What are allo-antibodies?
Allo-antibodies are pre-existing antibodies against other blood types
(T/F) Dogs have naturally occurring allo-antibodies
FALSE. Dogs do not typically have naturally occurring allo-antibodies present
What is the significance of dogs not typically having naturally occurring allo-antibodies?
Because dogs do not typically have naturally occurring allo-antibodies, this means that for their first transfusion, it is safe to transfuse any blood type (though this is not best practice), however you will be required to cross-match any subsequent transfusions as the dog will have developed antibodies against the originally transfused blood type
Which blood type system is used in dogs?
DEA blood typing system
Which DEA blood type is most significant and why?
DEA 1.1 is highly antigenic and thus induces a profound immune response when administered to DEA 1.1 negative dogs, as the antibodies produced agaisnt the DEA 1.1 blood type are both haemolysins and agglutinins, which can cause a severe haemolytic transfusion reaction following subsequent transfusions
Which blood type should be transfused in dogs that are DEA 1.1 negative?
DEA 1.1 negative blood should be transfused to dogs wih DEA 1.1 negative blood
Which blood type should be transfused in dogs that are DEA 1.1 positive?
DEA 1.1 positive blood should be transfused to dogs wih DEA 1.1 positive blood
(T/F) Cats have naturally occurring allo-antibodies
TRUE.
What is the significance of cats having naturally occurring allo-antibodies?
Beacause cats have naturally occuring allo-antibodies, it is essential to administer the correct blood type even for their first transfusion
Which blood type system is used in cats?
AB blood typing system
What are the three blood types seen in cats?
A blood type
B blood type
AB blood type
What happens when a type A recipient receives type B blood?
Mild to moderate haemolytic transfusion reaction
What happens when a type B recipient receives type A blood?
**Severe ** haemolytic transfusion reaction
Which breeds of cat are more likely to have A blood types?
Siamese
Oriental
Domestic short hair
Domestic long hair
Which breeds of cat are more likely to have B blood types?
British short hair
Abyssinian
Persian
Devon rex
Which breed of cat is most likely to have an AB blood type?
Not AB is a very rare blood type
Bengal
What should you do if you do not have blood type tests available but you need to transfuse a cat in an emergency?
Cross-matching
What is cross-matching?
Cross-matching is a technique used to detect the presence of antibodies in the recipient blood against the components of the donor blood
What are the indications for cross-matching?
- If there has been a prior transfusion in a dog
- If the patient has an unknown history they may have had a transfusion before but there is no record of it
- When the long term benefits of the transfusion are crucial and you don’t want to risk delayed haemolysis
- Before transfusing cats if blood typing tests are unavailable
What is major cross-matching?
Major cross-matching is when you test the effect of the recipient plasma on the donor red blood cells
What is minor cross-matching?
Minor cross-matching is when you test the effect of recipient red blood cells on the donor plasma
When would you use minor cross-matching?
Minor cross-matching is used prior to plasma transfusions
Which methods can you use to carry out cross-matching?
In-house cross matching kits (most accurate)
Slide-based cross matching kits
Describe how you should carry out slide-based cross-matching
Carry out smears on four seperate slides:
1. For the first slide, use the donor plasma and donor red blood cells as a donor control slide
2. For the second slide, combine the donor plasma with the recipient red blood cells for your major cross matching
3. For the third slide, combine the donor red blood cells and the recipient plasma for your minor cross matching
4. For the fourth slide, use the recipient plasma and recipient red blood cells as a recipient control slide
If there is agglutination on your cross-matching slides, this indicates an incompatible match due to the presence of antibodies reacting with the donor blood products. If there is no agglutination, the match is likely compatible
List two examples of non-haemolytic transfusion reactions
Type 1 hypersensitivity
Febrile transfusion
What can you do to reduce the risk of type 1 hypersensitivity transfusion reactions?
Pre-treat the recipient with antihistamines
What is a febrile transfusion reaction?
A febrile transfusion reaction is a reaction to blood transfusion characterised by pyrexia and other inflammatory signs
List four examples of non-immunologic transfusion reactions
Infectious disease transmission
Hypocalcaemia
Volume overload
Bacteraemia
How can blood transfusions cause hypocalcaemia?
Blood transfusions can cause hypocalcaemia as the blood is stored with sodium citrate to prevent coagulation. The citrate will bind the the patients endogenous calcium when the blood products are administered, rendering the calcium inactive resulting in hypocalcaemia
Which ten factors are you looking for when selecting canine blood donors?
Age between 1 - 8 years
Ideally more than 25kg
Healthy and not receiving any medication
Fully vaccinated and wormed
No travel history outside of the UK
Has not received a previous transfusion
Has never had puppies and is not pregnant
Has a good temperament
Pre-transfusion PCV of more than 35%
Ideally DEA 1.1 negative
Why is it important to select canine donors with a good temparament?
Dogs with a good temperament are less likely to require sedative drugs during donation
Which ten factors are you looking for when selecting feline blood donors?
Age between 1 - 8 years
Weigh more than 4kg
Healthy and not receiving any medication
Fully vaccinated and wormed
FeLV and FIV negative
Mycoplasma haemofilis negative
No travel history outside of the UK
Has not received a previous transfusion
Pre-transfusion PCV of more than 35%
Blood type must be specific to the recipient
Which tests should you do on donors prior to blood donation to ensure they are healthy and fit for donation?
Complete blood count (CBC)
Packed cell volume (PCV)
Biochemistry
Urinalysis
How much blood can dogs and cats donate?
Dogs and cats can donate 10 - 20% of their blood volume every 8 weeks
What is the average blood volume in dogs?
90 ml/kg
What is the average blood volume in cats?
60 ml/kg
How much anticoagulant is required for each 10ml of blood collected from a donor?
1.3ml of anticoagulant per 10ml of donor blood collected
Describe how to correctly administer blood products
- Place an intravenous (IV) catheter into a peipheral vein. If venous access cannot be gained, an introsseous catheter can be used
- make sure to have a dedicated intravascular line for transfusions where only blood products and saline can be infused - Warm the blood to room temperature (do not microwave)
- Run the blood through the giving set which has a special in-line filter, and visually inspect the blood for clots
- The patient should be on a comfortable bed confined to a cage and should receive no food or medication during the transfusion
- Blood and blood products can be safely administered via certain types of infusion pumps and syringe drivers
What size IV catheter should use for administering blood products and why?
You should use a catheter larger then 22 gauge if possible to avoid haemolysis
Why is it important to warm blood products before transfusing them?
Warming blood products reduces their viscosity and, prevents patients from rapidly cooling, and minimises vasoconstriction
Why do you have to you use warmed blood products within 24 hours?
The warming process will promote bacterial growth so the blood products have to be used within 24 hours
How do you calculate how much blood you are going to administer to your recipient?
k = 90 for dogs
k = 60 for cats
How much plasma should you administer to your recipient during a plasma transfusion?
10 - 20ml/kg of plasma
How quickly should you administer blood products?
Begin with 0.5 - 2 ml/kg/hr for 30 minutes. If the patient is not experiencing any signs of a transfusion reaction you can begin increasing the volume
What is the maximum volume of blood products you should administer in hypovolaemic patients per hour?
20ml/kg/hr
What is the maximum volume of blood products you should administer in normovolaemic patients per hour?
5 - 10mls/kg/hr
To prevent volume overload
What is the maximum volume of blood products you should administer patients with cardiac or kidney dysfunction per hour?
2mls/kg/hr
To prevent volume overload and worsening the cardiac or kidney disease
What are some of the possible clinical signs of a transfusion reaction?
Restlessness
Nausea
Salivation
Vomiting
Faecal and/or urinary incontinence
Pyrexia
Facial oedema
Pruritis
Tachypnoea
Apnoea
Tachycardia
Seizures
Muscle tremors
Leg stretching
