Blood typing and transfusions

Question 1

How does the blood have blood types

Answer 1

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

Question 2

How do you get alloantibodies

Answer 2

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

Question 3

What happens if a blood type does not match the doner

Answer 3

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

Question 4

What are the common blood types of dogs

Answer 4

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?

Question 5

When do dogs get acute hemolytic tarnsfusion reactions

Answer 5

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

Question 6

When do immune antibodies show up in dogs after transfusions

Answer 6

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

Question 7

What is the most common dog blood type

Answer 7

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

Question 8

How do you do in house canine blood typing

Answer 8

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

Question 9

What are the requirements for a dog to be a blood donor

Answer 9

> 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

Question 10

How much blood can be safely collected form a dog

Answer 10

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

Question 11

What are the common feline blood types

Answer 11

The AB sysetm
A, B or, AB

Question 12

Where is type A common in cats

Answer 12

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

Question 13

Where is type B common in cats

Answer 13

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

Question 14

How common is AB blood in cats

Answer 14

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

Question 15

What is MiK in cats

Answer 15

Another blood cell antigen with alloantibodies
Currently not detected with typing

Question 16

What are the feline blood donor requirments

Answer 16

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

Question 17

How much blood can we safely collect from a cat

Answer 17

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

Question 18

What are the bovine blood types

Answer 18

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?

Question 19

What are the ovine blood types

Answer 19

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

Question 20

What are the equien blood tyeps

Answer 20

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

Question 21

What do you do for equine blood typing

Answer 21

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

Question 22

when should transfusion therapy be done

Answer 22

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

Question 23

what causes a transfusion reaction

Answer 23

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

Question 23

What tests should you preform to make sure a transfusion doesn’t cause any adverse effects

Answer 23

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

Question 25

What are the indications for a blood transfusion

Answer 25

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

Question 25

Clinical signs of excessive blood loss or decreased O2 carrying capacity

Answer 25

Hypothermia
Pale mm
CRT >2s
Tachycardia
Tachypnea
Hypotension
depressed/unresponsive

Question 26

How to administer a blood transfusion

Answer 26

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

Question 27

What are the common volumes of blood transfusions

Answer 27

1 unit = 450ml (dogs)
1 unit = 50-60ml (cats)
Volume guidelines
10ml/kg of packed RBCs
20ml/kg of whole blood

Question 28

Precautionary measures when giving blood transfusions

Answer 28

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

Question 29

What is fresh whole blood and what does it provide for transfusions

Answer 29

Recommended for acute haemorrhage, anemia, coagulation disorders, and thrombocytopenia
Provides
RBC
Plasma proteins
Viable platelets
All clotting factors

Question 30

What is stored whole blood and what does it provide for transfusions

Answer 30

Recommended for anaemic patients
Provides
RBC
Plasma protein
Stable coagulation factors including fibrinogen
NO platelets
NO FACTORS V AND VIII

Question 31

What are blood components for blood transfusions

Answer 31

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

Question 32

What changes in stored blood products

Answer 32

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

Question 33

What are some blood substitutes and when to use

Answer 33

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

Question 34

What are some common transfusion complications

Answer 34

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

Question 35

Why can hemolysis occur with a blood transfusion

Answer 35

Immunologic–due to donor and recipient incompatibility
Acute or delayed hemolysis
Non-immunologic–due to mishandling of RBCs

Question 36

Signs of a transfusion reaction are

Answer 36

Hyperthermia
Tachycardia
Tachypnea
Agitation/restlessness
Muscle tremors
Urticaria,pruritis–leading to anaphylaxis
Nausea, salivation, vomiting
Hypotension
SHOCK

Question 37

How do you treat a transfusion reaction

Answer 37

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

Question 38

What are some common ways to perform blood typing

Answer 38

The tube method
Gold standard
Only used in reference labs
Described on Pages 118-119 of your textbook
Card agglutination tests
Immunochromatography assay

Question 39

What is the card agglutination test

Answer 39

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

Question 40

Immunochromatographic assay is doen how

Answer 40

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

Question 41

How do you perform a crossmatch

Answer 41

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

Question 42

What does a cross match do

Answer 42

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

Question 43

When should you perform a cross match

Answer 43

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

Question 43

What is important to remember about future transfusions

Answer 43

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