Blood Transfusions

Question 1

Why do we transfuse blood?

Answer 1

• Major bleeds

- Failure of production

Question 2

How are blood groups established?

Answer 2

• Arise from antigens= something that provokes an immune response
• Red cell antigens are expressed on cell surface (proteins, sugars, lipids)
• Can provoke antibodies
• Glycans added to proteins or lipids on RBC

Question 3

What does the ABO gene encode?

Answer 3

Glycosyltransferase

Question 4

What do the A and B genes encode for?

Answer 4

Transferase enzymes

Question 5

What is the A antigen?

Answer 5

N-acetyl-galactosamine

Question 6

What is the B antigen?

Answer 6

Galactose

Question 7

What is the O gene?

Answer 7

A non-functional allele

Question 8

Describe the inheritance of blood groups.

Answer 8

A and B are co-dominant whilst O is recessive

Question 9

What does blood group B have antibodies against?

Answer 9

A

Question 10

What does blood group A have antibodies against?

Answer 10

B

Question 11

What does blood group O have antibodies against?

Answer 11

A and B

Question 12

What does blood group AB have antibodies against?

Answer 12

No antibodies

Question 13

Who is universal red cell donor?

Answer 13

Blood group O

Question 14

Who is the universal red cell recipient?

Answer 14

Blood group AB

Question 15

Who is the universal FFP donor?

Answer 15

Blood group AB

Question 16

Who is the universal FFP recipient?

Answer 16

Blood group O

Question 17

What can RhD negative individuals do during pregnancy or transfusion?

Answer 17

• They can make anti-D if exposed to RhD cells

- This can lead to transfusion reactions or haemolytic disease of the new-born

Question 18

What screening do blood donors undergo?

Answer 18

• Extensive ‘behavioural’ screening
• Sex, age, travel, tattoo
• Tested for ABO and Rh blood groups
• Screened for HepB/C/E, HIV, syphilis
• Variably screened for: HTLV1, malaria, West Nile virus, Zika virus…

Question 19

What are the components and products of blood?

Answer 19

Plasma

• Clotting or coagulation factors
• Albumin
• Antibodies

Buffy Coat

• Platelets
• White cells

Red Blood Cells

Question 20

What are some indications fro RBC transfusion?

Answer 20

• Severe acute anaemia
• Uncorrectable anaemia
• Surgery
• Sickle cell disease

Question 21

How are RBCs transfused?

Answer 21

• Stored at 4oC
• Transfuse over 2-4 hours
• 1 unit increments ~5 g/L

Question 22

How are platelets transfused?

Answer 22

• 1 dose platelets (=4 pooled or 1 apheresis donor)
• Increments 20-40 10^9/L
• Stored at ~22oC, shelf life 7 days
• Transfuse over 20-30 minutes

Question 23

When may platelets be transfused?

Answer 23

• Massive haemorrhage
• Bone marrow failure
• Prophylaxis for surgery
• Cardiopulmonary bypass

Question 24

What are the components of plasma?

Answer 24

• Fresh frozen plasma

- Cryoprecipitate

Question 25

What are the indications for FFP?

Answer 25

- Massive haemorrhage - DIC with bleeding - Prophylactic

Question 26

How is FFP used?

Answer 26

- 1 unit from 1 unit of blood | - Stored frozen, allow 30 minutes to thaw

Question 27

What are the lab tests for FFP?

Answer 27

PT and APTT

Question 28

What is the lab test for cryoprecipitate?

Answer 28

Fibrinogen

Question 29

How is cryoprecipitate stored?

Answer 29

Frozen, allow 20 minutes to thaw

Question 30

How are patients grouped and screened?

Answer 30

- ABO and RhD type - Checked against historical records - Screen for allo-antibodies in serum

Question 31

What is the direct Coombs test used for?

Answer 31

- Autoimmune haemolytic anaemia - Passive anti-D - Haemolytic transfusion reactions

Question 32

What is the indirect Coombs test used for?

Answer 32

Cross matching

Question 33

At what temperature do the ABO and Rh blood group systems usually react?

Answer 33

37C

Question 34

What blood is usually available within minutes?

Answer 34

O- red cells (AB plasma)

Question 35

What bloods are usually available uregently?

Answer 35

Type specific (ABO/RhD)

Question 36

What bloods take time and are non-urgent?

Answer 36

- Full cross match to select the correct ABO/RhD type | - If allo-antibodies choose antigen negative blood

Question 37

What is the definitive management for massive haemorrhage?

Answer 37

Rapid control of bleeding via intervention or surgery

Question 38

Once a massive haemorrhage protocol has been activated what is there an immediate supply of?

Answer 38

- 6 units red cells - 4 units FFP - 1 unit platelets

Question 39

What should decision to transfuse be based on?

Answer 39

The decision to transfuse should be based on a careful assessment of patient's clinical state and must be justified as essential to prevent major morbidity or mortality

Question 40

How is prion disease transmittable?

Answer 40

By blood transfusion from early in the disease

Question 41

How should transfusion reactions be managed?

Answer 41

- Stop transfusion - Check patient identity against component label - Consider: anaphylaxis, circulatory overload (TACO), acute haemolytic transfusion reaction (AHTR), bacterial infection, lung injury (TRALI) (other…)

Question 42

Acute transfusion reaction: possible cause of pyrexia

Answer 42

FNHTR

Question 43

Acute transfusion reaction: possible cause of urticaria

Answer 43

- Mild allergic reaction | - Anaphalaxis

Question 44

Acute transfusion reaction: possible cause of dyspnoea

Answer 44

- TACO - TRALI - Anaphylaxis

Question 45

Acute transfusion reaction: possible cause of shock

Answer 45

- IBCT - Anaphylaxis - TRALI - TAS

Question 46

Acute transfusion reaction: treatment for pyrexia

Answer 46

- Antihistamine | - Other symptoms usually more concern (bronchospasm/shock)

Question 47

Acute transfusion reaction: treatment of dyspnoea

Answer 47

- O2 - Diuretic - Ventilation - Adrenaline

Question 48

Acute transfusion reaction: treatment of shock

Answer 48

- Adrenaline(IV)/Hydrocortisone/Antihistamine - IV fluid / ITU admission - Ventilation - Antibiotics, - FFP/platelets if DIC

Question 49

What is sensitisation in rhesus disease?

Answer 49

Development of maternal anti D antibodies

Question 50

Does IgG cross the placenta?

Answer 50

Yes

Question 51

How does haemolytic disease of the new-born present at birth?

Answer 51

- Positive direct antiglobulin test - Jaundice - Anaemia

Question 52

How is HDN prevented?

Answer 52

Using prophylactic anti-D at 28/40 weeks or during sensitising events

Question 53

What is the treatment for HDN?

Answer 53

Careful monitoring - Antibody titres - Doppler ultrasound - Intrauterine transfusions

Question 54

What is TRALI?

Answer 54

Transfusion related acute lung injury - Transfused anti-leucocyte Abs in donor plasma interact with patient’s WBC - Bilateral pulmonary infiltrate - Supportive management, ventilation