13. Blood Typing and Transfusions Flashcards
What are alloantibodies?
naturally occuring antibodies against another blood type of the same animal species
May be present even if anim has not previously been exposed to foreign blood group antigen
Seen in CATS,
cattle, pigs, sheep and horses w/ prev exposure
Which species does not have alloantibodies?
Dogs
When might Ab-Ag reaction occur?
When blood transfusions btw recipient and donor have diff blood group antigens
Cells clump/agglutinate, may = RBC lysis
What happens when you give a mismatched transfusion to a patient?
The recipient animal will prod Ab to the RBC Ag of the donor
immune antibodies
What are the canine blood types?
> 12 groups
DEA: dog Erythrocyte Antigens
DEA 1 (subtypes, 1.1, 1.2, 1.3), DEA 3 - DEA 7
Dog is reported as pos or ned for a given DEA
Clinically significant are DEA 1 and 7
DAL
KAI 1/KAI 2
When might an acute hemolytic transfusion reaction occur in a DEA 1, DEA 4 and DAL neg dogs?
When they have recieved >1 blood transfusions
Dogs not born w/ alloantibodies
if pos blood is transfused into a neg patient w/ a 1st transfusion - a delayed reaction can occur up to 1 wk later
severe reactions w/ subsequent transfusions can occur 1hr after
When do immune ab’s appear in canines?
7-10 days post exposure to a mismatched blood type
transfusion reactions occur at the rate of 15% on unmatched donor-recipient combos
What % do DEA 7 make up of the populations?
45%
transfusion of DEA 7+ blood into a DEA 7- animal may = delayed hemolytic reaction
What is the universal donor for dogs?
negative for DEA 1 and 7
What canine blood types can rapid vet test for?
DEA 1, 4, 5 and DAL
should be considered w/ subsequent transfusions and incompatible crossmatch results
What are the canine blood donor requirements?
> 25kg, 1-9yr
No more than 1x/4wks
Neg for 1.1 and 1.2 and preferably 3, 5 and 7
Vx’s up to date
no prior blood transfusions
Spayed/neutered
no prior pregnancies
normal CBC, biochemical profile and neg for brucella canis
neg parasite test (blood/fecal)
on a heartworm preventative
well-nourished
How much blood can we safely collect from a dog?
Total blood volume is about 90mL/kg lean BW
should not exceed 10-15% of total blood volume to prevent signs of hypovolemia
Therefore, we should not collect more than 9-13ml/kg BW
What are the feline blood types?
A, B and AB
How common is type A feline blood?
very common
94-99% of cats in N. America
Do not react as strongly to type b blood as type b cats react to type A blood
How common is type B cat blood?
Uncommon in SK
common in purebreds - devon rex, british shorthair, abyssinian, Main coon, persian
More common in Australia
Prod very strong Anti A alloantibodies
due to naturally occurring antibodies, ALL cats must be crossmatched b4 1st transfusion
What are type AB cat blood?
Extremely rare
have no naturally occuring 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?
another blood cell Ag w/ alloantibodies
currently not detected w/ typing
No universal donor in cats
What is the feline blood donor requirements?
btw 1-9 yrs, no more than 1x/3wks
No prior transfusions
PCV prior to donation - min 30%
Blood parasite free (toxoplasma gondii, mycoplasma hemofelis)
Screen: CBC, FeLV, FIV, chem panel
Neg fecal exam, vx’s, no prev preg
How much blood can we safely collect from a cat?
total blood volume ~66ml/kg lean BW
should not exceed 10-15% of total blood volume to prevent signs of hypovolemia (if >10% collected) patient should be put on IV fluids
therefore, should not collect more than 6.5-10mL/kg BW
What are the bovine blood types?
11 diff groups
A, B, C, F, J, L, M, R, S, T, and Z
Group B has 60 diff Ag
J-pos donors can cause reactions bc of anti-j alloantibodies
no universal donor, blood replacement products a better choice?
What blood types do ovines have?
7 groups
A, B, C, D, M, R and X
group B has several Ag’s
May have R alloantibodies
neonatal isoerythrolysis can occur in lambs given bovine colostrum
What are the different blood types of equines?
8 group systems >30 blood groups - A, C, D, K, P, Q and U
naturally occurring Ab’s exist but likely due to vx’s containing equine tissue or transplacental immunization
No universal donor - type AaCa w/ neg Ab screen recommended as donors
Crossmatch!
transfution reactions occur and are severe/can be fatal
mare-foal incompatibility test - crossmatching procedure to detect Ab in mare’s serun to foal erythrocytes
What is transfusion therapy?
should ONLY be done after blood typing and cross-matching
If dog has never has transfusion/been preg, an unmatched transfusion can be given in emerg (can still have delayed reaction
Mismatched samples can = in a transfusion reaction which can be fatal or cause ineffective therapy
What reproductive status of a species should always be typed and cross-matched.
Breeding females to avoid primary sensitization and risks for future offspring - horses/cats
Cross-matching easily done in clinic
Canine blood typing is currently limited to DEA 1, 4, 5 and DAL and feline A, B, and AB
What blood components might we use instead of blood?
platelet rich plasma, packed RBCs and plasma may be available
ability to tailor to tx to specific requirements of patient
When might we transfuse?
Anemic patients
Trauma victims
Catastrophic blood vessel injury
Why might we do transfusions in trauma victims?
hypovolemic shock bc of internal hemorrhage - splenic or liver lacerations, these highly vascular organs bleed rapidly and excessively and are difficult to manage as they are non-compressible
Ext hemorrhage is easier to recog and tx
What is catastrophic blood vessel injury
may or may not be compressible - ext: apply tourniquet or compress area
Int: often require sx correction
What are some clinical signs of excessive blood loss or decreased O2 carrying capacity?
hypothermia
pale MM
CRT >2 seconds
Tachycardia
Tachypnea
Hypotension
depressed/unresponsive
How are transfusions administered?
blood is filtered b4 admin or while given - use in-line filters that retains blood clots, platelet microaggregates, WBCs and fat
Warm to 37C in water bath
concurrent fluid therapy 0.9% saline - avoid calcium containing solutions LRS bc it’ll cause clots to void
- Avoid hypotonic solutions bc of RBC lysis
What is the maximum rate of administration for blood? Exceptions?
10ml/kg/hr, except those from hypovolemic shock
What might you pretreat before administering a blood transfusion?
diphenhydramine 1-2mg/kg IM or SQ
How long do we have before the transfusion needs to be complete?
4 hours to prevent contam of blood suppy
What is the volume to be administered based upon for blood transfusions?
BW, estimated blood V, hematocrit, and goal of therapy
1 unit = 450ml (dogs)
1 unit = 50-60ml (cats
Volume guidelines:
10ml/kg of packed RBCs
20 ml/kg of whole blood
What are some precautionary measures to take with blood transfusions?
blood type and cross match
use 0.5-1ml/kg/hr of whole blood for the first 15-30 mins as a test dose
watch for reaction, if no, proceed w/ infusion
What does fresh whole blood provide to a patient? What are its indications
Provides: RBCs, plasma proteins, viable platelets, all clotting factors
Indications: acute hemorrhage, anemia, coagulation disorders, and thrombocytopenia
What does stored whole blood provide, indications
provides: RBCs, plasma proteins, stable coagulation factors including fibrinogen, NO platelets, NO FAVTORS 5 and 8
What are blood components?
Packed RBCs for Anemic but not hypovolemic patients
Plasma - to inc blood volume, provides immunoglobulins, provides coagulation factors
What might changed in stored blood products?
dec pH, calcium, 2,3-DPG, ATP
Inc ammonia lvls, potassium ions in some japanese breeds like akitas and shiba inus
bacterial proliferation/contamination
What are blood substitues?
Oxyglobin - blood collected aseptically from cattle and filtered to remove the Hgb from rest of RBC
Hgb structure is similar btw species, it is minimally Ag - no need for typing or cross matching
labelled for use in dogs but also has been used off label in cats, horses, llamas, birds and humans
What are some transfusion complciations?
hemolysis - immunologic (due to donor-recipient incompatibility - acute or delayed) or non-immunologic (due to mishandling of RBCs)
Hemoglobinemia, hemoglobinuria, DIC, Acute renal failure, death
Non-hemolytic allergic reactions
volume overload/overly rapid delivery - pulmonary edema
bacterial contamination of blood
hypocalcemia
disease transmission
dec PCV
What are the signs of a transfusion reaction?
hyperthermia, tachycardia, tachypnea, agitation/restlessness, muscle tremors
urticaria, pruritis - leading to anaphylaxis
nausea, salivation, vomiting
hypotension
SHOCK
How do we treat for transfusion reactions?
STOP the transfusion and alert the DVM
admin IV crystalloids
Dexamethasone 0.25mg/kg given IV slowly
Diphenhydramine 2mg/kg given IM q8h
Epinephrine (1:10,000) 0.1mg/kg IM
the protocol should be determined by the vet b4 transfusion beigins
What happens to treatment if the reaction is mild?
can try to restart transfusion @ slower admin rate WHILE MONITORING PATIENT CLOSELY
What are the diff ways to blood type?
Tube method - gold standard, only used in ref labs
Card agglutination test
immunochromatography assay
What are card agglutination tests
rapid Vet-H
fast an accurate
samples must be free of autogluttination
cards available for typing dogs (dea 1, 4, 5 and DAL + and -) and typing cats A, B, or AB
uses monoclonal Ab’s specific to erythrocyte Ags being tested for
requires whole blood in an EDTA tube
What is the immunochromatographic assay?
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
What is cross matching?
used to detect whether agglutination or hemolysis are likely to occur when the donor and recipient blood samples are mixed > serological incompatibility - recudes the likelihood of a transfusion reaction
Should be done prior to any transfusion, but especially when: animal had a blood transfusion at least 3-4 days earlier, unknown donor hx, donor blood type unknown, breeding female
What is a major crossmatch?
2 drops of recipient plasma are mixed w/ 2 drops of washed donor cells
What is a minor cross match
2 drops of donor plasma are mixed with 2 drops of washed recipient cells
What are cross matching controls?
2 drops of donor plasma is mixed w/ 2 drops of washed donor cells AND 2 drops of recipient plasma mixed w/ 2 drops of washed recipient cells
Incubate for 15-30m
centrifuge for 5m and examine the tubes for evidence of hemolysis or agglutination
What are some important concerns about crossmatching?
cross matching does NOT prevent sensitization of patient to future transfusions
even though a specific blood donor is compatible w/ patient. if 5+ days have passed since 1st transfusion and additional transfusions, another crossmatch MUST be performed
