Blood transfusion

Question 1

what are the components of blood offered by the transfusion service

Answer 1

red cells
platelets
fresh frozen plasma
cryoprecipitate

Question 2

how are blood components obtained

Answer 2

centrifuging anti-coagulated blood to separate it

Question 3

one unit of the blood components comes from one/many donors

Answer 3

one

Question 4

what are the blood products offered by the transfusion therapy

Answer 4

human albumin 
IV immunoglobulin 
human normal immunoglobulin 
tetanus, hep B etc immunoglobulins 
anti-D immunoglobulins 
prothrombin complex concentrates

Question 5

blood products come from one/many donors

Answer 5

many

Question 6

how is the safety of the blood ensured

Answer 6

exclude infective risk from donor - tonsillitis, flu etc
exclude risk of disease transmission - malignancy, neuro conditions of uncertain aetiology (MS)
donor encouraged to get in contact if they become ill

Question 7

what are the 4 blood groups in the ABO group

Answer 7

group A (carry A antigen)
group B (carry B antigen)
group AB (carry A and B antigens) 
group O ( doesn't carry or B)

Question 8

what antibodies will group O carry

Answer 8

A and B

Question 9

what antibodies will group A carry

Answer 9

B

Question 10

what antibodies will group B carry

Answer 10

A

Question 11

what antibodies will group AB carry

Answer 11

none

Question 12

what is the universal donor blood type

Answer 12

type O - no antibodies against this blood type

Question 13

what is the universal recipient blood type

Answer 13

type AB - these people have produced no antibodies against blood

Question 14

what is the least and most common blood types

Answer 14

least common - AB

most common - O

Question 15

what type of antibodies are the naturally occurring ABO-antibodies

Answer 15

IgM (mostly)

some IgG

Question 16

which chromosome has the genes which determine blood group

Answer 16

chromosome 9

Question 17

out of the A, B and O genes, which are dominant/recessive

Answer 17

A and B are co-dominant

O is silent/recessive

Question 18

what genotype gives the O phenotype

Answer 18

OO

Question 19

what genotype(s) give the A phenotype

Answer 19

AA or AO

B is therefore BB or BO

Question 20

what genotype gives AB phenotype

Answer 20

AB

Question 21

which chromosome is responsible for determining Rh(D) protein

Answer 21

chromosome 1

Question 22

genotypes that give RhD positive

Answer 22

DD or Dd

Question 23

when can someone go from RhD negative to RhD positive

Answer 23

when exposed to RhD positive red cells:
pregnancy with RhD positive foetus
blood transfusion

develops antiD antibody

Question 24

consequences of giving RhD positive blood to someone who is RhD negative

Answer 24

no issues on first transfusion - this is when they form the antibody
could cause delayed haemolytic transfusion reaction after further transfusions

Question 25

what is the reaction called when antibody is introduced to corresponding blood cells

Answer 25

agglutination - cross links red cells

Question 26

when is agglutination used in the laboratory

Answer 26

to determine someone's blood type

Question 27

what puts someone at risk for irregular antibodies (not naturally occurring ABO ones)

Answer 27

previous pregnancy | previous blood transfusions

Question 28

indications for red cell transfusion

Answer 28

anaemia (if untreatable cause or life threatening) | acute blood loss

Question 29

indication for frozen plasma

Answer 29

bleeding in surgery with liver disease and impaired coagulation coagulopathy following massive transfusion disseminated intravascular coagulation

Question 30

indication for platelet transfusion

Answer 30

low platelets symptoms of bleeding underlying infection

Question 31

risks of transfusions

Answer 31

immediate haemolytic transfusion reaction delayed haemolytic transfusion reaction febrile non-haemolytic transfusion reactions urticarial reactions circulatory overload bacterial/viral infection

Question 32

what is immediate haemolytic transfusion reaction

Answer 32

the transfusion of incompatible red cells (e.g. A donor to O recipient)

Question 33

what happens when antibodies bind to RBCs in circulation

Answer 33

activates complement cascade, coagulation system and kinin system

Question 34

what happens when complement cascade is activated

Answer 34

C3a and C5a activate the membrane attack complex - leads to rupture of transfused cells increased vascular permeability dilated vessels release of serotonin and histamine (fever, chills, hypotension, hsock)

Question 35

what happens when kinin system activated

Answer 35

activated by Factor XII formation of bradykinin (dilatation and increased permeability) hypotension catecholamine release - vasoconstriction in kidneys

Question 36

clinical features of immediate haemolytic transfusion reaction

Answer 36

``` pyrexia and rigors faint/dizzy tachycardia and tachypnoea hypotension headaches cyanosis ```

Question 37

management of acute haemolytic transfusion reaction

Answer 37

stop transfusion IV fluids blood samples - FBC, coag, U+E, cultures

Question 38

how long after transfusion does delayed haemolytic transfusion occur

Answer 38

5-10 days

Question 39

what is febrile non-haemolytic transfusion reactions

Answer 39

recipient has anti-HLA antibodies which binds to residual white cells

Question 40

clinical features of febrile non-haemolytic transfusion

Answer 40

rapid temp rise | chills/rigors

Question 41

investigations if suspected febrile non-haemolytic transfusion reaction

Answer 41

look for HLA antibodies | double check red cells were compatible

Question 42

management of febrile non-haemolytic reactions

Answer 42

if transfusion is non-urgent, stop and exclude more serious reaction can give anti-pyretics (paracetamol) before transfusion as prophylaxis

Question 43

risk factors for circulatory overload in blood transfusions

Answer 43

elderly | congestive cardiac failure