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
What is the appropriate management for ABO incompatibility?
Stop transfusion Check patient and component Repeat cross match and DAT
26
What are the symptoms of bacterial contamination of blood?
Presents very similar to wrong blood - shock, increased temp, restless, fever, vomiting, collapse
27
How does bacterial contamination of blood cause symptoms?
Bacterial growth --> endotoxin which causes immediate collapse
28
Recall some protocols for prevention of bacterial contamination of blood
Donor questionning Arm cleaning Diversion of first 20mls of blood Proper storage
29
Which patients are at most risk of anaphylactic reaction to a blood transfusion?
Those with IgA deficiency
30
How quickly does TACO/TRALI present?
Within 6 hours
31
What does TACO stand for?
Transfusion-associated circulatory overload
32
What are the symptons of TACO?
SOB, decreased SaO2, increased HR and BP (due to pulmonary oedema)
33
What should be checked pre-transfusion to reduce the risk of TACO?
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
What is the probably cause of TRALI?
Antibodies
35
What is the main difference in the management of TACO and TRALI?
TRALI doesn't repsond to furosemide
36
What is the pathophysiology of delayed haemolytic transfusion reaction?
Development of an 'immune' antibody to a RBC antigen they lack ('allo-immunisation')
37
Over what time period does delayed haemolytic transfusion reaction develop?
5-10 days
38
Recall 2 clinical features of delayed haemolytic transfusion reaction
DAT positive | Jaundiced
39
What is the prognosis of transfusion-associated GVHD?
Always fatal
40
Which patients are most at risk of transfusion-associated GVHD?
Severely immunosuppressed
41
What is the cause of transfusion-associated GVHD?
Failure to destroy donor lymphocytes completely
42
How can transfusion-associated GVHD be prevented?
Irradiate blood for immunosuppressed patients
43
What are the symptoms of transfusion-associated GVHD?
Severe diarrhoea Liver failure Skin desquamation Bone marrow failure
44
How long after a transfusion do post-transfusion purpura present?
7-10 days
45
How should post-transfusion purpura be treated?
IV Ig
46
What is the main complication risk of post-transfusion purpura?
Big bleeding
47
How can iron overload be prevented?
Chelation (Exjade)
48
When are pregnant women checked for RBC Immunoglobins during pregnancy, to prevent GVHD?
12 and 28w gestation
49
If a pregnant woman has RBC antibodies that put the baby at risk of GVHD, what should be done?
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
What is the anti-D dosing during pregnancy?
Before 20w, 250iu | After 20w, minimum 500iu
51
How does anti-D work during pregnancy to prevent GVHD?
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
How quickly must anti-D be given following sensitisation events?
Within 72 hours
53
Recall some examples of sensitising events
``` Spontaneous miscarriages Amniocentesis/ CVS Abdominal trauma External cephalic version Still birth ```
54
What is the routine anti-D prophylaxis for mother's with no obvious sensitising events?
1500iu anti-D at 28-30w gestation