Transfusion Flashcards
What can rat bait cause in regards to the trachea?
Narrowing of the trachea due to a bleed- essentially a long haematoma that occurs around the trachea- causing tracheal narrowing
Treating haemorrhagic shock
Large loss of blood, reduction of circulating volume that creates a lot of issues. Goal: stabilize. Use crystalloids first (electrolytes essentially), colloids second- larger molecules, transfusion is the 3rd go to because it is with risk, and it is expensive.
Other than trauma, second most common reason for transfusions?
Anaemia- destruction- production- consumption/loss. Animals with a haematocrit level of 9, normal is 40
Canine blood donor
Good temperment (lay down for 5-10 minute), volume removed from jugular vein- reasonably visible, no other health problems, vaccinated, >25 kg to allow collection of full unit (450 ml), negative for blood borne disease in your area, should never have received a transfusion, blood typed
Feline Blood donor
> 5kg body weight (for 50 mL to be collected), no other health problems, FeLV/FIV/Mycoplasma negative, Ideally indoor cat, donors of both blood groups required
Blood types, difference in cats and dogs when it comes to transfusion reactions?
Antigens on the surface of RBCs, circulating antibodies to the antigens must already be present for a transfusion reaction to occur
- *Dogs do not have naturally occurring alloantibodies (antibodies that are already circulating)– they would only produce those if they had a transfusion in the past
- *Cats DO have naturally occurring alloantibodies
How many blood types in dogs? Examples?
8 blood tops
Dog erythrocyte antigen system (DEA) DEA 1.1, 1.2, 3, 4, 5, 7 (1.1 is the most antigenic one) All greyhounds are negative
**Universal donor- in other words, negative for all antigens- almost impossible to find- you would have to screen 1000 dogs- not feasible
Neg blood–> neg recepient–> ?
No Ab production
Pos blood–> neg recepient–> ?
Ab production
Pos blood–> sensitised dog–> ?
Haemolytic rxn
General rules of thumb- negative blood to who? positive blood to who?
- negative blood to negative or positive recipient
* positive blood to positive recipients
Cat blood types
A>B»AB (very rare), type B common in AUS. Always have to type cats because strong alloantibodies especially type B against A antigen. So if you gave A blood to a B cat, it would be destroyed straight away
Could you give type A cat, type B blood?
20% of type A cats have weak anti-B antibodies. In theory you could give them B blood.
Does a type AB cat have alloantibodies?
No alloantibodies to A or B. Use AB blood or A if AB not available.
Cross matching
Mixing donor and recipient blood looking for agglutination or haemolysis
Evaluates compatibility between donor and recipient at that point in time
Collection of blood
Animals should be able to donate up to once monthly without becoming anaemic (typical frequency every 3 months), PCV should be checked, physical exam, don’t use animals that are pyrexic
Sterile collection is key- sterile glove, sterile skin prep
Open vs. closed system
Only opening is the initial needle stick. Blood is a good breeding ground for bacteria, so very key. Closed system. This is the only way you can store blood.
How long can you store blood and with what?
- 21-35 days
- anticoagulant and some nutrients for cells. (citrate, phosphate, dextrose, adenine)- 2,3 DPG and ATP better maintained.
- ADSOL can be used to increase storage time. (additive solution)
Why citrate over heparin?
Heparin would make recipient coagulopathic (citrate for fresh whole blood only)
Why can’t you store cat blood?
Normally take it with a needle, so not a closed system. You take so much less.
How is plasma stored? PCV?
Plasma is frozen, PCV is in the fridge
Giving transfusion
Do not warm more than 39C.
Takes time to warm to room temperature.
Water bath at 37C
Start slowly 2-5 ml/hr for 20 minutes to allow early recognition of transfusion reactions. Check patient demeanour and TPR every 5 minutes.
** as fast as you need to in peracute, life threatening situations (3-4 units within an hours if massive bleeding)
** give each unit over 4 hours- check patient every 30 minutes
Whole blood used?
When need RBCs, plasma proteins, coag factors, platelets (functional). Best way to give platelets.
Haemorrhagic shock, coagulopathy coupled with anaemia
Packed red blood cells given?
Anaemia where intravascular volume is normal (haemolysis e.g. IMHA, decreased production, slow, chronic loss like a GI bleed or fleas)
Given with asanguineous fluids for whole blood loss (crystalloids, FFP)
Asanguineous
Resembling blood. Crystalloids, FFP (fresh frozen plasma)
Euvolaemia
Normal circulating volume
When to give a transfusion?
Especially with acute anaemia, hypovolaemia, factors that affect oxygen delivery are decisive- i.e. Hb, SaO2, Cardiac output
When do transfuse based on PCV?
30% best tissue O2 delivery, 20% compromised O2 delivery, 15% increased lactate
FFP
Fresh frozen plasma- all clotting factors, antithrombin, and anti-inflammatory proteins. Thaw slowly in warm water bath. Disorders of secondary haemostasis (i.e. rodenticides, SIRs/ sepsis, DIC), 20 ml/kg is a good starting point
Frozen Plasma
Loses some clotting factors (mainly V and VIII) and anti-inflammatory proteins. Still provides vitamin K dependent factors II, VII, IX, X
Cryoprecipitate
Involves thawing to a slush and then separating- can be stored for a further year. Mainly for vWF and Factor VIII
Platelet Rich Plasma
used within 3-5 days. Thrombocytopenic animals- many units needed to provide adequate platelets. Reserved for larger specialty centers.
When to transfuse platelets
Difficult to collect and store. FWB is easiest source. Reserved for life threatening bleeding due to thrombocytopenia (intracranial, pulmonary, massive GI bleed, perioperative)
