blood groups Flashcards
hw are blood groups determined
according to antigens expressed on the surface of erythrocytes (generally glycoproteins or glycolipids
what are alloantibodies
- specific antibodies directed against erythrocyte antigens (blood types) present in the same species but not in the individual producing the antibody
- extremely important in determining the success or failure of a blood transfusion
- the presence of antibodies directed against RBC antigens will reduce survival of transfused cells (= transfusion reaction)
- may have their effect by agglutination and/or hemolysis of RBCs
- can occur naturally or can be acquired by exposure to the blood group antigen
how are blood group systems classified in dogs
dogs have a number of different blood types but pen side tests (snap test/cards) only test if the dog is blood type DEA1.1 (dog erythrocyte antigen)
how are blood group systems classified in cats
- cats have 3 different blood groups: A, B and rarely AB
- highly immunogenic
- prevalence of blood groups varies between countries and with breed
how are blood group systems classified in horses
when would you perform a blood transfusion
- clinical condition of the patient (anemia patient with signs of cardiovascular compromise like tachycardia, tachypnoea, collapse)
- OR PCV <10%
- OR PCV has fallen rapidly to <20% in dogs <15% in cats
- OR during surgery if there is major hemorrhage
how do you calculate how much blood to transfuse
- rule of thumb: 2 ml whole blood/kg of body weight raises PCV by 1%
- calculation based on donor PCV: (image for calc)
- dose rate: 1-4 ml/kg/hr
why is transfusion useful
rarely a cure –> provides support while an underlying cause is could +/- treatment started
aim is for clinical improvement rahter than obtaining a normal PCV. post transfusion PCV of 25-30% in dogs and 20% in cats`
in dogs, the blood type snap test card determines
if blood group is DEA1.1 or not
in cats the blood type snap test determines
all blood types of that species
blood typing is essential for
all blood transfusions in cats
blood cross matching is recommended prior to transfusion for
dogs that had a previous blood transfusion
what is the criteria for blood donors
- between 1 and 8 years old
- healthy, not on any medication
- good PCV
- fully vaccinated and wormed
- good temperament
- never had a blood transfusion
- never travelled abroad
- collection of less than or equal to 10% of total blood volume to ensure no adverse effect
- collection of less than or equal to 20 % of total blood volume should not result in clinically significant anemia provided to donor has a normal PCV at collection (can produce hypovolemia in the short term)
- PCV > 35%
incats: (~66 ml blood/kg)
- over 4.5 kg
- must test negative for FIV and FelV
- female donors should have had no previous pregnancies and should be neutered
- 40-50ml collected
- blood group known
in dogs (~90 ml blood/kg)
- over 25 kg
- ~450 ml collected at pet blood bank
- ideally DEA1.1 negative
what is Patch’s blood group
AB
what is tigger’s blood type
B
what is the PCV of a normal dog
25-45%
what is the test result and what does it tell you about rio’s blood group
rio has blood group DEA1.1. test result is DEA1.1 positive
what is the best route for administration for blood transfusion?
A. peripheral vein (i.e. cephalic)
B. central veing (i.e. jugular)
C. intra osseous route
all three
rio has had a previous blood transfusion before with no issues. does this make a transfusion reaction more of less likely
more likely because most problems arise after the 1st transfusion if antibodies have been formed in response to it and 2nd transfusion is of the same blood group (allo-antibodies)
do transfused erythrocytes have a longer, shorter or the same lifespan as the body’s own
shorter
how does the regeneration of red blood cells impact the blood profile over the first week
- macrocytic
- hypochromic
- regenerative
which element of the clotting cascade is affected with anticoagulant redenticides
vitamin K
which hemostasis pathways are affected when clotting factors are depleted due to vitamin K deficiency
- extrinsic
- intrinsic
- common
the integrity of which pathways does prothrombin time measure
extrinsic and common pathways
for prothrombin time, if henry has consumed redenticide, what do you expect to see
prolonged
the integrity of which pathways does activated partial thromboplastin time measure
intrinsic and common pathways
for activated partial thromboplastin time (time taken to clot), if henry consumed rodenticide, what would you expect to see
prolonged
based on the below hematology tests, what type of anemia does henry have
macrocytic, hypochromic regenerative
you have 500 ml of blood availible for transfusion. a a general rule of thumb, blood can be transfused at a rate of 5-10 ml per kg per hour. henry weighs 30.5 kg. calculate the flow rate you have to set your infusion pump at for a transfusion of 10 ml per kg per hour. how many hours will it take to transfuse 500 ml
flow rate: 305 ml/hr
total time: 98 min or 1 hr. 38 min
(10ml/kg)x30.5 kg = 305 ml/hr
(500 ml/1)x(1hr/305ml) = 1.64 hr x 60 = 98 min