Blood Groups and transfusion medicine Flashcards
What are the different types of blood group antigens?
- Naturally occurring alloantibodies
- Acquired
Cats can have naturally occurring antibodies against other blood groups
What type of antibodies do Type A cats have?
what about type B?
and Type AB?
- Type A carry weak anti-type B antibodies
- Type B carry very strong anti-type A antibodies
- Type AB carry no antibodies against type A or B antigens
Blood typing in cats is vital
What blood types are siamese cats more likely to be?
What blood type are BSH, Rex’s and Ragdolls more likey to be?
Some pedigree cats are almost invariably type A: Siamese and derivative breeds
Some pedigree cats have high incidence of type B: BSH, Rex’s and Ragdolls
Out line the guidlines for feline blood transfusion?
- ideally transfuse with own blood type
- if B blood given to A type cat - will destroy quickly, not fatal reaction
- If A type or AB type blood given to a B type cat - strong antibodies - fatal reaction
- Can give type A or Type B blood to AB type cat
When can you not blood type a cat before a transufusion?
Never!! - ALL DONOR AND RECIPIENT CATS **MUST BE BLOOD TYPED **PRIOR TO TRANSFUSION, EVEN IN AN EMERGENCY!
What is Feline neonatal isoerthrolysis?
What are the symptoms?
who can this be avoided
Type A or AB kittens born from a type B queen
RBCs in the kittens are targeted by “anti-A” antibodies from the queen (which are present naturally in type B cats from approx. 3mo)
These transfer from colostrum while < 24h old
‘Fading’ kittens
- Red/brown urine, jaundice, anaemia, sudden death; varies subclinical to severe
Breeders should be urged to type queen (and the tom if queen found to be type B
What is the only canine blood group that can be tested for?
How are canine blood groups described?
DEA 1 antigen has the most transfusion significance (highly antigenic) - only group commertially testable
Dogs are described as DEA 1 positive (~70%) or DEA 1 negative (~30%)
Certain breeds more likely to be a particular type
Dogs do not have pre-formed antibodies against non-self canine blood types
outline the guidlines for blood transfusion in dogs
Where possible should always blood type and give matched blood
* DEA 1+ve –> DEA 1+ve
* DEA 1 -ve –> DEA 1-ve
In emergencies we can give un-typed transfusions but it’s not recommended.
DEA 1 –ve should be used as this can be given to +ve or –ve dogs
Why should DEA 1 +ve blood should only be administered to a DEA 1+ve patient?
- This will prevent sensitizing a DEA 1-ve dog to the DEA 1 antigen
- Also reduce chance of delayed haemolytic reaction (4 days)
Subsequent administration of DEA 1 +ve to a sensitised DEA –ve dog can produce a acute haemolytic transfusion reaction –> Potentially fatal! - if a dog has had a transfusion before you should always type them
What are the differnt types of cross matching?
Test that looks for potential reactions between a donor’s and patient’s blood
These show as agglutination or haemolysis
Major cross match
* Compatibility between donor red blood cells and patient plasma/serum
* Incompatibility means the donor cannot be used!
Minor cross match
* Assesses compatibility between donor plasma/serum and patient RBCs.
* Incompatibility means only washed or PRBC should be used (but this cant be done in most first opinion practices)
What are the three ways to cross match blood?
DIY This can be done in house through a complex mixing of the patient and donor RBCs and plasma and then assessing for agglutination and or haemolysis.
Kit Rapid Vet-H gel cross-match kit
**Submit to commercial lab **(e.g.idexx) - takes a while not suitable for emergency
Why do we cross match blood?
when should you cross match?
- Additional blood groups that can’t be tested in-house
- Dogs can have many blood types that coexist (Dal, DEA 4)
- Cats likely to have additional blood types recognised (e.g. Mik)
Cats naturally occurring antibodies means cross-matching is always recommended…only exception is for xeno transfusion.
Dogs
* If recipient has been previously transfused >2d prior
* History of previous transfusion reaction
* Transfusion history unknown
Will need to be repeated with each subsequent transfusion
(if >2d in between)
In urgent cases sometimes incompatible blood has to be used try to use the least reactive and call the lab for advice on which to use.
What are the aims of blood transfusion?
replace the missing component of blood and in the case of conditions such as anaemia and haemorrhage, to increase the oxygen carrying capacity.
What are the different indications for blood transfusion?
Acute vs Chronic is often a big determining factor
Triggers:
* Evidence for circulatory collapse means transfusion is essential
* Rapid drop in PCV to < 20% in dogs or < 15% in cats (e.g. 10% or more)
* Absolute PCV of 15-20%: dependent on historical and clinical signs
* PCV < 10-12%, automatic trigger as organ hypoxia is imminent (myocardium)
* Signs of specific organ hypoxia – particularly CNS
* Evidence for reduced oxygen carrying capacity
* Tachycardia, tachypnoea, bounding peripheral pulse (rapid rise and fall of pulse)
What is fresh blood?
What is stored blood?
What are the indications for this?
Fresh (FWB)
Storage length: 8hours room temperature.
Contains: all components of blood
Only product available currently in UK with some level of platelets, but must be used within 6 hours for this.
Stored (SWB)
Storage: 21 days, Refrigerated (2-6C)
Contains: Lacks PLTs, WBCs and labile clotting factors
**Primary indication **- acute blood loss or active bleeding.
Consider an autotransfusion if no sign of neoplasia.
What is a Autologous transfusion?
What are the idications?
what are the contraindications?
What are the benefits?
Using the patients own blood
Indications: Acute intraoperative bleed
Contraindications: Neoplasia/ Contamination
Benefits: Reducing potential for exposure to allogenic blood, reduces risk of (new) infectious diseases, reduces chance of transfusion reactions, immediate availability
What is a xeno transfusion?
What are the indications?
Waht are the contrainications?
What are the things ot remember?
Using a different species blood
Indications: Emergency need and no feline blood available.
Especially B. Or will take too long to get blood from donor.
Contraindication: Previous xeno transfusion
Things to remember: Do not last long (can be 24hr)
Can lead to AkI and other complications
Needs clear owner understanding and consent
What are the primary indications for pack red blood cells?
Whole-blood can be centrifuged to separate RBCs from the plasma
Storage: 2-6C, 42 days, mix regularly. Contents: PRBC only
Primary indication: Any patient developing clinical signs of low tissue oxygenation due to anaemia
Only available for dogs in this country currently.
What are the different types of plasma?
What are the indications of each?
Frozen in 24h of collection = **fresh frozen plasma (FFP) **
Longevity: (shelf life 1 year)
Contents: labile and non-labile clotting factors
Main indication: coagulopathies
Frozen>24h after collection/FFP after 1 year =**frozen plasma (FP) **
Longevity: (shelf life additional 4 years)
Contents: non-labile clotting factors
Main indication: Non-labile clotting factor needs such as toxicities causing coagulopathies, haemophilia B
What is cryoprecipitate?
What is the indication?
Plasma fraction separated from fresh frozen plasma
Storage: shelf life 1 year: needs controlled thawing and centrifugation.
Contains: concentrated product labile clotting factors
* Fibrinogen
* Factor VIII
* Von Willebrands factor.
Main Indication: Pre-treatment for vWD deficiency
What is cryosupernatan?
What is the indication?
Remaining fraction after cryo-precipitate is produced
Storage: shelf life 1 year
Contains: plasma proteins
Albumin, Vitamin K dependant clotting factors II, VII, IX and X.
Main indication: Non-labile clotting factor needs such as toxicities causing coagulopathies, haemophilia B
What is the criteria for a canine blood donner?
- Fit and healthy
- 2-8 yo
- > 25Kg (max 16-28ml/kg)
- Good temperament
- Never travelled abroad/ Been pregnant
- Vaccinated (not within 14d) flea/wormed
- Not on any medication
- Not donated in the last 12 weeks
What is needed to be done before a blood donation is made?
What equipment is needed?
- Perform full physical health check
- Haematology and biochemistry pcv>40%
- Blood typing (Cross match if needed)
Equipment required
* 3 people
* Prep solution
* 450ml blood collection bag with CPD/CPD-A (anticoagulant)
* Electronic weigh scales
* Macro-clamp-P
* Tube stripper
* Soft bed and treats
What is the process for taking canine blood?
- Prepare the collection bag as per manufacturer guidelines
- 2 assistants hold dog in lateral recumbency on table
- Venipuncture in jugular vein
- Release clamp and blood should flow to the bag easily
- Regularly rock the collection bag to mix with anticoagulant
- 480g (450ml)
- Clamp line
- Remove needle and apply neck bandage
- Use the tube stripper to strip the blood in the line.
- Check demeanour, HR, mm quality and pulse quality
- Offer small amount food and water
*
What is the criteria for a feline blood donor?
- Healthy
- Friendly
- 2-8 yo
- > 4.5kg lean bodyweight (Max 12ml/kg)
- Vaccinated (not within 14d) flea/wormed
- No history of pregnancy or on medication
- Preferably indoor cat
- No donated in the last 12 weeks
What pre-checks should be done before feline blood donation?
- Perform full physical exam (consider cardiac U/S)
- Full haematology/biochem – PCV>35%
- FeLV/FIV (If outdoor at each donation)
- Blood type
- Mycoplasma haemofelis pcr negative but external test so not always possible.
- PBB recommend an echo but as a bare minimum a Tfast
- Crossmatch
What is an essential step for blood donation in cats?
Sedation required - small vessles and unhappy to stay still
- Butorphanol and alphaxan to effect
- Can add in midazolam
What are the equipment is needed for blood donation in cats?
- 4 people: Handler, Phlebotomist, Assistant, Anaesthestist
- Monitor
- Intubation tray and anaesthetic machine
- Butterfly catheter
- 10/20ml luer tip syringe
- Three way tap
- Source of CPDA-1/CPD (1.25ml/10ml)
- Macroclamp P
- Comfy bed
What needs to be done post op with a cat blood donor?
Administer hartmanns post procedure twice the donation amount over 2-3 hours
what are the key parts for the administration of the blood product?
- monitoring for patient
- Filtered giving set
- or in case of cats/smaller dogs or autotransfusion – Hemo-Nate filter on the end of the syringe
How much blood product should be given to patients?
- 2ml transfused whole blood/kg recipient weight raises PCV by 1%
- 1ml transfused packed red blood cells/kg recipient weight raises recipient PCV by 1%
What rate should you transfuse blood?
Stable patients, initial infusion rate of **0.5-1.0ml/kg/hr **
* 15-30 minutes
* Monitor for evidence of transfusion reaction
If no reaction, can be increased to 4-6ml/kg/hr complete in 4 hours!
In an emergency (e.g. severe acute haemorrhage), red cells can be given as fast as necessary
This applies for plasma products too.
how do you administer a blood transfusion?
- Blood products need to be prepared carefully
- Warm to 37C
- Consent must be obtained
- Should be given IV (peripheral or central)
- Intraosseous can be used in moribund patients
- Administration via filtered giving set
- A specific blood product drip pump must be used.
- Monitor every 5min for 30min then every 15-30min
- TPR, resp effort, CRT, mm colour, IV and mentation.
- Monitor post transfusion for delayed reaction.
Transfusions should not be administered through the same IV line as any solutions containing Ca or gluc
How can trasfusion reactions be classified?
- Timing - acute vs delayed
- Pathophysiological mechanism - immunological vs non-immunological reactions
What are the imminological and non-immunological transfusion reactions?
Immunological:
* Haemolytic
* Non-haemolytic
Non –immunologic: Not mediated through immune mechanisms
* Circulatory overload
* Bacterial contamination
* Hypothermia
* Citrate toxicity
* Dilutional coagulopathy
* Hyperammonaemia and acidosis
* Disease transmission
What are the causes of acute heamolytic transfusion reactions?
What are the clinical signs?
What are the treatments?
Causes
* Blood type incompatibility
* Class II (antigen-antibody) hypersensitivity reaction – acute intravascular haemolysis
* Uncommon (particularly in horses and dogs)
* Type B cat administered type A or AB blood
* DEA 1 –ve dogs sensitised to DEA 1 and repeated exposure
Clinical signs: may include: fever, tachycardia, dyspnoea, muscle tremors, V+, weakness, collapse, haemoglobinaemia, haemoglobinuria, shock, death
Treatment: Transfusion should be STOPPED immediately
* IV fluids
* +/- corticosteroids
What is a delayed haemolytic transfusion reaction ?
What are the causes?
what are the clinical signs?
what is the treatment?
Extravascular haemolysis 3-21d post transfusion
Causes: May occur in dogs administered incompatible blood on first transfusion
**Clinical signs: **
* Reduced lifespan of donated erythrocytes (Post-transfusion PCV rapidly declines)
* Hyperbilirubineamia +/- bilirubinuria
Treatment
Specific treatment generally not required
What is a fibrile non-haemolytic transfusion reaction?
What are the clincial signs?
What is the treatement?
Acute PLT/WBC hypersensitivity
* Most common Transfusion reaction with whole blood
* Leukoreduction can help minimise this
**Clinical signs: **Temp > 39C
Treatment: Rule out other reactions first. None life threatening, can try at a slower rate.
What is an acute hypersensitivity transfusion reaction?
What are the clinical signs?
What is the treatment?
Anaphylactic (allergic type I hypersensitivity)
IgE antibodies which activate mast cells
Clinical signs: Minor skin reactions such as pruritus and urticaria to more severe such as hypotensive shock
Treatment: STOP the transfusion
For milder reactions – antihistamines + corticosteroids
Severe signs – intensive shock therapy
How do you avoid transfusion reactions?
- Blood typing (essential in cats)
- Cross matching (preffered in cats)
- Appropriate donor screening
- Correct handling of products:
- Aseptic collection,
- Preparation during administration
- Appropriate storage
What is the therapeutic plan for a transfusion reaction?
If suspect transfusion reaction – STOP transfusion
1. Clinical exam: TPR haemoglobinaemia/haemoglobinuria
2. Supportive treatment as indicated
Can include…
IVFT, antihistamines, adrenaline
corticosteroids, antihistamines,
Oxygen, diuretics
1. Check blood type/cross-match
2. Check blood for lysis
What is the clinical presention of transfusion reactions?
Increase in temperature
Change in the respiratory/heart rate
Change in mm colour
Visible oedema
GI signs
More severe signs also possible
Patients should be monitored throughout the transfusion and for the following 24 hours
