Blood typing and transfusions Flashcards
How does the blood have blood types
RBCs have structures on their surface called antigens
All of an animals RBCs will have the same type of RBC antigen
These antigens are genetically determined and are called blood group antigens
Alloantibodies are naturally occurring antibodies against another blood type of the small animal species
How do you get alloantibodies
May be present even if the animal has not previously been exposed to the foreign blood group antigen
Most clinically relevant in cats
Alloantibodies are not present in every species
Also seen in cattle, pigs, sheep and horses with previous antigen exposure
What happens if a blood type does not match the doner
Antigen-antibody reactions can occur when blood transfusions between a recipient and donor have different blood group antigens
Creates cell clumping or agglutination
May also result in RBC lysis
If a mismatched transfusion has occurred, the recipient animal will produce antibodies to the RBC antigens of the donor
These are called immune antibodies
The number of blood groups per species varies significantly
Blood typing can be performed at reference labs or within the clinic to maximize the safety of blood transfusions
What are the common blood types of dogs
There are more than a dozen blood groups have been identified in dogs
Many are labelled as DEA: dog erythrocyte antigens
DEA 1 (subtypes 1.1, 1.2, 1.3) DEA 3, DEA 4, DEA 5, DEA 7
The dog is reported as + or -’ve for a given DEA
The most clinically significant antigens are DEA 1 and DEA 7 in most cases
DAL
Kai 1/ Kai 2
Others?
When do dogs get acute hemolytic tarnsfusion reactions
Acute hemolytic transfusion reactions can occur in DEA 1/4 and DAL -’ve dogs that have received more than one blood transfusion
Dogs are not born with alloantibodies
If + blood is transfused into -’ve patient with a first transfusion – a delayed reaction can occur up to 1 week later
Severe reactions can occur with subsequent transfusions in as little as 1 hour after receiving the blood products
When do immune antibodies show up in dogs after transfusions
Immune antibodies will begin to appear 7-10 days post exposure to a mismatched blood type
Transfusion reactions occur at the rate of 15% on unmatched donor-recipient combinations
What is the most common dog blood type
DEA 7 + dogs make up about 45% of the population
Transfusion with DEA 7+ blood into a DEA 7- animal may result in a delayed hemolytic reaction
A dog that is negative for a DEA 1 and 7 is considered the ideal universal donor
How do you do in house canine blood typing
Rapid vet makes canine blood typing kits for
DEA 1
DEA 4
DEA 5
DAL
Should be considered with subsequent transfusions and incompatible crossmatch results
What are the requirements for a dog to be a blood donor
> 25 kg
1-9 years of age; some will only use donors up to 7 years of age
Frequency: no more than once every 4 weeks
Negative for 1.1 and 1.2 and preferably 3, 5, and 7
Vaccinations are up to date
No prior blood transfusions
Spayed or neutered
No prior pregnancies
Normal CBC, biochemical profile and negative for Brucella canis
Negative parasite tests (blood and fecal)
On a heartworm preventative
Well nourished
How much blood can be safely collected form a dog
Total blood volume is about 90mL/kg lean body weight
We should not exceed 10-15% of total blood volume to prevent signs of hypovolemia
Therefore, we should not collect more than 9-13ml/kg body weight
What are the common feline blood types
The AB sysetm
A, B or, AB
Where is type A common in cats
Very common
94-99% of cats in north america
Do not react as strongly to type B blood as type B cats react to type A blood
Where is type B common in cats
Uncommon in saskatchewan
More common in some purebred cats
More common in australia
Produce very strong anti-A alloantibodies
Due to naturally occurring antibodies, all cats must be cross matched before their first transfusion
How common is AB blood in cats
Extremity rare
Have no naturally occurring alloantibodies
Should receive type AB blood; difficult to obtain
Substitute type A if necessary which will be compatible or only slightly incompatible in the minor cross match
What is MiK in cats
Another blood cell antigen with alloantibodies
Currently not detected with typing
What are the feline blood donor requirments
Between 1-9 years of age
Frequency: no more than once every 3 weeks
No prior transfusions
PCV prior to donation- minimum 30%
Blood parasite free (toxoplasma gondii, mycoplasma haemofelis)
Screen: CBC, FeLV, FIV and chemistry panel
Negative fecal examination
Vaccinations are up to date
No previous pregnancies
How much blood can we safely collect from a cat
Total blood volume is about 66ml/kg lean body weight
We should not exceed 10-15% of total blood volume to prevent signs of hypovolemia (if >10% collected, the patient should be put in IV fluids)
Therefore we should not collect more than 6.5-10 ml/kg body weight
What are the bovine blood types
11 different blood groups
Designated A, B,C, F, J, L, M, R, S, T, and Z
Group B has 60 different antigens
J- positive donors can cause reactions
anti-J alloantibodies
No universal donor, blood replacement products a better choice?
What are the ovine blood types
Seven blood groups
Designated A,B,C,D,M,R, and X
Group B has several antigens
May have R alloantibodies
Neonatal isoerythrolysis can occur in lambs given bovine colostrum
What are the equien blood tyeps
Eight major blood group systems, .30 blood groups- A,C,D,K,P,Q,and U
Naturally occuring antibodies exist but are likely due to vaccinations containing equine tissue or transplacental immunization
What do you do for equine blood typing
No universal donor
Type AaCa with a negative antibody screen recommended as donors
Crossmatching
Transfusion reaction are often sever and can be fatal
Mare-foal incompatibility test
Cross Matching procedure to detect antibodies in mares serum (or colostrum) to foal erythrocytes
when should transfusion therapy be done
Should only be done after blood typing and cross matching
If a dog has never had a transfusion of been pregnant, an unmatched transfusion could be given, but this should only be done in an emergency situation
First transfusions can still cause a delayed reaction
what causes a transfusion reaction
Mismatched samples can result in a transfusion reaction which could be fatal or cause ineffective therapy
Breeding females should always be typed and cross matched to avoid primary sensitization and risks for future offspring
Horses and cats
What tests should you preform to make sure a transfusion doesn’t cause any adverse effects
Horses and cats
Cross matching is easily performed in the clinic
Canine blood typing is currently limited to DEA 1, 4, 5 and DAL and Feline A,B, and AB
Make sure to take an accurate history and to determine if the animal has had any previous pregnancies or transfusions
Blood components such as platelet rich plasma, packed red blood cells and plasma may be available
Ability to tailor the treatment to the specific requirements of the patient
What are the indications for a blood transfusion
Anemic patients
Many causes
Hemolysis
Hemorrhage
Trauma victims
Hypovolemic shock resulting from
Internal haemorrhage
Spelic or liver lacerations
These highly vascular organs beel rapidly and excessively
Difficult to manage as they are non-compressible
External hemorrhage
Easier to recognize and treat
Catastrophic blood vessel injury
May pr may not be compressible
External: apply tourniquet or compress the area
Internal: often require surgical correction
Stabilise patient
Clinical signs of excessive blood loss or decreased O2 carrying capacity
Hypothermia
Pale mm
CRT >2s
Tachycardia
Tachypnea
Hypotension
depressed/unresponsive
How to administer a blood transfusion
Blood is filtered before administration or while it is being given
Use in line filters– retains blood clots, platelet microaggregates, WBCs and fat
Warm blood products to 37*C in a water bath
Concurrent fluid therapy in 0.9% saline
Avoid calcium containing solutions (LRS) – clot formation
Avoid hypotonic solutions (5% dextrose in water or hypotonic NaCl) – RBC lysis
Maximum rate of administration is 10ml/kg/hr, except in those suffering from hypovolemic shock
Recipient may be pretreated
Diphenhydramine 1-3mg/kg IM or SQ
Administer IV using strict aseptic technique
Complete the transfusion within 4 hours to prevent contamination of the blood supply
Volume to be administered us based in body weight, estimated blood volume, hematocrit and the goal of therapy
What are the common volumes of blood transfusions
1 unit = 450ml (dogs)
1 unit = 50-60ml (cats)
Volume guidelines
10ml/kg of packed RBCs
20ml/kg of whole blood
Precautionary measures when giving blood transfusions
Blood type and crossmatch
Use 0.5-1ml/kg/hr of whole blood for the first 15-30min as a test dose
Watch for signs of reaction
If none, proceed with the transfusions
What is fresh whole blood and what does it provide for transfusions
Recommended for acute haemorrhage, anemia, coagulation disorders, and thrombocytopenia
Provides
RBC
Plasma proteins
Viable platelets
All clotting factors
What is stored whole blood and what does it provide for transfusions
Recommended for anaemic patients
Provides
RBC
Plasma protein
Stable coagulation factors including fibrinogen
NO platelets
NO FACTORS V AND VIII
What are blood components for blood transfusions
Blood often stored after having been split into its various components
Packed RBC
For patients that are anaemic but not hypovolemic
Plasma
Used to increased blood volume
Provides immunoglobulins
Provide coagulation factors
What changes in stored blood products
Decreased pH
Decreased calcium
Decreased 2,3-DPG
Decreased ATP
Increased ammonia levels
Increased potassium ions in some japanese breeds of dogs
Bacterial proliferation/contamination
What are some blood substitutes and when to use
Due to the problems of finding compatible donors and disease transmission, a substitute for blood has been sought
Oxyglobin
Blood is collected aseptically from cattle and filtered to remove the Hgb from the rest of the RBC
The Hgb structure is similar between species, it is minimally antigenic
There is no need for typing or crossmatching
Labelled for use in dogs but has also been used off label in cats, horses, llamas, birds and humans
What are some common transfusion complications
Hemolysis
Hemoglobinemia
Hemoglobinuria
DIC
Acute renal failure
Death
Allergic reactions that are non-hemolytic
Volume overload/overly rapid delivery
Pulmonary edema
Bacterial contamination of blood
Hypocalcemia
Disease transmission
Decreased PCV
If a transfusion reaction occurs, it means that the transfusion is not doing the intended job
There are added complications for an already compromised patient
Why can hemolysis occur with a blood transfusion
Immunologic–due to donor and recipient incompatibility
Acute or delayed hemolysis
Non-immunologic–due to mishandling of RBCs
Signs of a transfusion reaction are
Hyperthermia
Tachycardia
Tachypnea
Agitation/restlessness
Muscle tremors
Urticaria,pruritis–leading to anaphylaxis
Nausea, salivation, vomiting
Hypotension
SHOCK
How do you treat a transfusion reaction
STOP the transfusion and alert the veterinarian
Administer intravenous crystalloids
Dexamethasone 0.25mg/kg given IV slowly
Diphenhydramine 2 mg/kg given IM Q8H
Epinephrine (1:10,000) 0.1mg/kg IM
The protocol should be determined by the veterinarian before the transfusion begins
IF the allergic reaction is mild, you can try to restart the transfusion at a slower administration rate WHILE MONITORING THE PATIENT CLOSELY
What are some common ways to perform blood typing
The tube method
Gold standard
Only used in reference labs
Described on Pages 118-119 of your textbook
Card agglutination tests
Immunochromatography assay
What is the card agglutination test
Brand–Rapid Vet-H
Fast and accurate
Samples must be free of autoagglutination
Cards are available for
Typing dogs as DEA 1, 4, 5 and DAL positive or negative
Typing cats as A, B or AB
Uses monoclonal antibodies specific to the erythrocyte antigens that are being tested for Requires whole blood in an EDTA tube
Immunochromatographic assay is doen how
A rapid and accurate test method
Very similar to the canine heartworm test
Lines indicate the patient’s blood type
Uses a positive control for each test
How do you perform a crossmatch
Major Crossmatch: 2 drops of recipient plasma are mixed with 2 drops of washed donor cells
Minor Crossmatch: 2 drops of donor plasma are mixed with 2 drops of washed recipient cells
Controls: 2 drops of donor plasma is mixed with 2 drops of washed donor cells AND 2 drops of recipient plasma is mixed with 2 drops of washed recipient cells
Incubate for 15-30 minutes
Centrifuge for 5 minutes and examine the tubes for evidence of hemolysis or agglutination
Procedure is described if further detail on Page 120 in your textbook
Commercial cross matching kits are also available
What does a cross match do
Used to detect whether agglutination or hemolysis are likely to occur when the donor and recipient blood samples are mixed→ serological incompatibility
Reduces the likelihood of a transfusion reaction
When should you perform a cross match
Should be done prior to any transfusion, but especially when:
The animal had a blood transfusion at least 3-4 days earlier
Unknown donor history
Donor blood type unknown
Breeding female
What is important to remember about future transfusions
Cross matching does NOT prevent sensitization of the patient to future transfusions
Even though a specific blood donor is crossmatch compatible with the patient today, if 5 or more days have passed since the first transfusion and additional transfusions are needed, another crossmatch MUST be performed
