Haematology 13: Blood Transfusions 1 Flashcards

1
Q

What happens in Haemolytic disease of the newborn ?

A
  • RhD -ve mother has a RhD positive child and comes into contact with the blood during pregnancy/ or has a RhD +ve blood transfusion.
  • The mother now makes anti-D
  • The next baby is RhD +ve and this time the anti-D antibodies (IgG) cross the placenta
  • This causes a delayed haemolytic reaction

Haemolytic disease of the newborn or severe foetal anaemia an heart failure (hydrops fetalis)

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2
Q

How does indirect antiglobulin technique work to screen blood ?

A
  • Blood recipient’s plasma is put into test tube (contains recipient antibodies)
  • Blood donor’s red cells are added to the test tube (has antigens)
  • If the recipient has antibodies against the donor’s red cells they will form antigen-antibody complexes
  • Coombs antibody is added (anti-human antibody)
  • This causes cross linking if immune complexes are present
  • if agglutination takes place the blood is not matched
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3
Q

What is the universal donor group for RBC ?

A

O- (no antigens on cells)

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4
Q

What is the universal donor group for plasma ?

A

AB (no antibodies in plasma)

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5
Q

Which method of blood transfusion is more acceptable for jehova’s witnesses ?

A

Cell salvage (collection, filtration and return of blood lost during surgery)

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6
Q

Why do patients with immunosuppression require irradiation of blood products ?

A

The donor lymphocytes can start reacting to self antigens and mount an immune response

This is known as transfusion associated graft versus host disease (TA-GvHD)

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7
Q

Which immune deficiency causes severe allergic reactions to donor blood plasma ?

A

IgA deficiency

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8
Q

Name 2 haematological diseases in which platelet transfusion is strongly contraindicated ?

A

HIT - heparin induced thrombocytopenia

TTP- thrombotic thrombocytopenic purpura

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9
Q

What is prothrombin complex concentrate (PPC) ?

A

A blood product containing vitamin K dependent clotting factors 10, 9, 7 and 2

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10
Q

what happens if you give ABO incompatible blood

A

intravascular haemolysis

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11
Q

what type of antibody are immune anti-D antibodies

A

IgG
do not cause direct agglutination of RBCs
not immediate haemolysis and death
delayed haemolytic transfusion reaction

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12
Q

what other Rh antigens are there

A

C, c, E, e, Kell (K), M, N, Duffy (Fy), Kidd (Jk)

Duffy and Kidd also cause delayed haemolytic transfusion reactions

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13
Q

what is given when there is an incompatibility between the mother and fetus in terms of Rh

A

give prophylactic anti-D immunoglobulin

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14
Q

what is reverse group testing

A

known A and B group RBCs are mixed with the patients plasma (IgM antibodies)
positive result = agglutination at the top

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15
Q

what are two types of crossmatching

A

full crossmatch - patients plasma combined with donor RBC at 37 degrees for 30-40 mins
immediate spin - incubate patients plasma and donor RBC for 5 mins and spin to detect ABO abnormalities (in emergencies)

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16
Q

what compatibility is needed for :

  • RBC
  • Platelets
  • Plasma
A

RBC - ABO/D compatible
Plasma - ABO
Platelets - D

17
Q

how are RBC stored

A

4 degrees 35 days

transfuse 1 unit over 2-3 hours

18
Q

how are platelets stored

A

22 degrees 7 days

transfuse 1 unit over 20-30 mins

19
Q

how is plasma stored

A

frozen up to 1 yr

transfuse 1 unit over 20-30 mins

20
Q

list 3 indications for blood transfusion

A

major blood loss, >30% blood volume lost
peri-op critical care Hb <70g/L
post chemo Hb <80

I RBC should cause a 10g/L increase in Hb in a 70-80kg patient

21
Q

what 3 ways can your own blood be transfused

A

peri-operative autologous deposit - not done in UK
intra-operative cell salvage - blood collected, centrifuged, filtered, washed, re-infused
post-op cell salvage - filtered and re-infused

22
Q

what are 2 special transfusion requirements

A

CMV negative blood - intra-uterine and neonatal transfusions

Irradiated - highly immunocompromised (Ta- GvHD)

23
Q

what 2 drugs can cause platelet dysfunction

A

aspirin

clopidogrel

24
Q

3 indications for FFP

A

massive transfusion - blood loss > 150ml/min
DIC - with bleeding
liver disease + risk - PT ratio >1.5x normal

25
Q

what is the treatment of choice to reverse warfarin

A

PCC
prothrombin complex concentrate
contains factors 2,7,9,10