Haematology 14 - Blood Transfusion 1 & 2 Flashcards

1
Q

Recall 2 ways in which patients’ blood group is tested

A
  1. Using anti-A,B and O reagents against the patient’s red blood cells
  2. Also use ‘reverse group’ - known A and B group RBCs against the patient’s plasma
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2
Q

Describe the process of antibody testing of blood

A

Group and screen

  • Use 2 or 3 reagent red blood cells containing all the important RBC antigens between them
  • Then incubate the patient’s plasma using the indirect antiglobulin technique
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3
Q

What is the purpose of ‘immediate spin’ blood testing?

A

Used in emergencies only
Incubation for just 5 minutes
Determines ABO compatibility only

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4
Q

What are the 3 pillars of patient blood management?

A
  1. Optomise haematopoiesis
  2. Reduce bleeding (eg stop anti-platelt drugs, cell-salvage techniques)
  3. Harness and optomise physiological tolerance of anaemia
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5
Q

For which blood products is D compatibility required?

A

Red cells and platelets (but not FFP or cryoprecipitate)

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6
Q

What is the storage temperature of red cells, platelets, FFP and cryoprecipitate?

A

Red cells: 4 degrees C
Platelets: 20 degrees C
FFP: 4 degrees C once thawed
Cryoprecipitate: Room temp once thawed

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7
Q

What is the storage length of red cells, platelets, FFP and cryoprecipitate?

A

Red cells: 35 days
Platelets: 7 days
FFP: 24 hours
Cryoprecipitate: 4 hours

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8
Q

What is the transfusion rate of red cells, platelets, FFP and cryoprecipitate?

A

Red cells: 1 unit over 2-3 hours
Platelets: 1 unit over 20-30 mins
FFP: 1 unit over 20-30 mins
Cryoprecipitate: 1 unit over 20-30 mins

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9
Q

How much blood loss counts as ‘major’?

A

> 30% blood volume lost

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10
Q

When are platelets contra-indicated?

A

TTP/ heparin-induced TTP

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11
Q

How low does haemaglobin need to be to require transfusion peri-operatively vs post-chemo?

A

Peri-op/ crit care: <70g/dL

Post-chemo: <80g/dL

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12
Q

In what type of surgery is post-operative cell salvage most often done?

A

Knee surgery

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13
Q

What are the steps of intra-operative cell salvage?

A

Centrifuge, filter, wash and re-infuse blood

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14
Q

What special blood reuquirements do pregnant women have?

A

CMV neg

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15
Q

What special blood reuquirements do highly immunocompromised patients have?

A

Blood needs to be irradiated

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16
Q

What special blood requirements do patients who have had severe reactions in the past to transfusion have?

A

Washed cells

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17
Q

Recall the 10 classes of transfusion reaction, and which are acute/ delayed?

A

Acute (<24 hours):

  1. Acute haemolytic (ABO incompatible)
  2. Allergic/ anaphylaxis
  3. Bacterial infection
  4. Febrile non-haemolytic
  5. TACO/TRALI

Delayed:

  1. Delayed haemolytic transfusion reaction (antibodies)
  2. Transfusion-associated GVHD
  3. Infection (malaria, CJD)
  4. Post-transfusion purpura
  5. Iron overload (thalasaemia patients mostly)
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18
Q

What monitoring should be done during a blood transfusion as minimum?

A
  1. Baseline temp, HR, RR, BP
  2. Repeat obs after 15 mins
  3. Repeat hourly after end of transfusion
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19
Q

What are the features of febrile non-haemolytic transfusion reaction?

A

Temp increase >1%

Chills and rigors

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20
Q

Why is febrile non-haemolytic transfusion reaction rare nowadays?

A

Blood is now leucodepleted to reduce risk of febrile non-haemolytic transfusion reaction

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21
Q

How should febrile non-haemolytic transfusion reaction be managed?

A

Stop/ slow the transfusion and give paracetamol

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22
Q

What is the pathophysiology of febrile non-haemolytic transfusion reaction?

A

Cytokines released by white blood cells during storage cause a febrile reaction upon transfusion

23
Q

What should be the management of an allergic transfusion reaction?

A

Stop/ slow transfusion

IV antihitamines

24
Q

What are the symptoms of ABO incompatibility?

A

Shock and fever

Restlessness, fever, vomiting and collapse

25
Q

What is the appropriate management for ABO incompatibility?

A

Stop transfusion
Check patient and component
Repeat cross match and DAT

26
Q

What are the symptoms of bacterial contamination of blood?

A

Presents very similar to wrong blood - shock, increased temp, restless, fever, vomiting, collapse

27
Q

How does bacterial contamination of blood cause symptoms?

A

Bacterial growth –> endotoxin which causes immediate collapse

28
Q

Recall some protocols for prevention of bacterial contamination of blood

A

Donor questionning
Arm cleaning
Diversion of first 20mls of blood
Proper storage

29
Q

Which patients are at most risk of anaphylactic reaction to a blood transfusion?

A

Those with IgA deficiency

30
Q

How quickly does TACO/TRALI present?

A

Within 6 hours

31
Q

What does TACO stand for?

A

Transfusion-associated circulatory overload

32
Q

What are the symptons of TACO?

A

SOB, decreased SaO2, increased HR and BP (due to pulmonary oedema)

33
Q

What should be checked pre-transfusion to reduce the risk of TACO?

A

Check the patient is not always in positive fluid balance

Check they don’t have risk factors for TACO - if they do, they need a aprophylactic diuretic

34
Q

What is the probably cause of TRALI?

A

Antibodies

35
Q

What is the main difference in the management of TACO and TRALI?

A

TRALI doesn’t repsond to furosemide

36
Q

What is the pathophysiology of delayed haemolytic transfusion reaction?

A

Development of an ‘immune’ antibody to a RBC antigen they lack (‘allo-immunisation’)

37
Q

Over what time period does delayed haemolytic transfusion reaction develop?

A

5-10 days

38
Q

Recall 2 clinical features of delayed haemolytic transfusion reaction

A

DAT positive

Jaundiced

39
Q

What is the prognosis of transfusion-associated GVHD?

A

Always fatal

40
Q

Which patients are most at risk of transfusion-associated GVHD?

A

Severely immunosuppressed

41
Q

What is the cause of transfusion-associated GVHD?

A

Failure to destroy donor lymphocytes completely

42
Q

How can transfusion-associated GVHD be prevented?

A

Irradiate blood for immunosuppressed patients

43
Q

What are the symptoms of transfusion-associated GVHD?

A

Severe diarrhoea
Liver failure
Skin desquamation
Bone marrow failure

44
Q

How long after a transfusion do post-transfusion purpura present?

A

7-10 days

45
Q

How should post-transfusion purpura be treated?

A

IV Ig

46
Q

What is the main complication risk of post-transfusion purpura?

A

Big bleeding

47
Q

How can iron overload be prevented?

A

Chelation (Exjade)

48
Q

When are pregnant women checked for RBC Immunoglobins during pregnancy, to prevent GVHD?

A

12 and 28w gestation

49
Q

If a pregnant woman has RBC antibodies that put the baby at risk of GVHD, what should be done?

A
  1. Check if Father has the antibodies (were they inherited?)
  2. Monitor Ig level
  3. Check ffDNA sample
  4. Monitor foetus for anaemia
  5. Deliver baby early
50
Q

What is the anti-D dosing during pregnancy?

A

Before 20w, 250iu

After 20w, minimum 500iu

51
Q

How does anti-D work during pregnancy to prevent GVHD?

A

RhD pos foetal cells get covered in anti-D Ig

Mother’s reticulo-endothelial system removes coated cells (spleen) before they get chance to sensitise mother

52
Q

How quickly must anti-D be given following sensitisation events?

A

Within 72 hours

53
Q

Recall some examples of sensitising events

A
Spontaneous miscarriages
Amniocentesis/ CVS
Abdominal trauma
External cephalic version
Still birth
54
Q

What is the routine anti-D prophylaxis for mother’s with no obvious sensitising events?

A

1500iu anti-D at 28-30w gestation