Blood Transfusions

Question 1

Why do we transfuse blood?

Answer 1

• mainly because of bleeding
• but also because of failure of production

Question 2

Describe the inheritance of blood groups.

Answer 2

A and B are co-dominant whilst O is recessive

Question 3

What does blood group B have antibodies against?

Answer 3

A

Question 4

What does blood group A have antibodies against?

Answer 4

B

Question 5

What does blood group O have antibodies against?

Answer 5

A and B

Question 6

What does blood group AB have antibodies against?

Answer 6

No antibodies

Question 7

Who is universal red cell donor?

Answer 7

Blood group O negative

Question 8

Who is the universal red cell recipient?

Answer 8

Blood group AB positive

Question 9

Who is the universal FFP donor?

Answer 9

Blood group AB positive

Question 10

Who is the universal FFP recipient?

Answer 10

Blood group O negative

Question 11

What can happen to RhD negative individuals during pregnancy or transfusion?

Answer 11

• They can make anti-D if exposed to RhD cells
• This can lead to transfusion reactions or haemolytic disease of the new-born

Question 12

What screening do blood donors undergo?

Answer 12

• 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 13

What are the components and products of blood?

Answer 13

• Plasma
  
  • Clotting or coagulation factors
  • Albumin
  • Antibodies
• Buffy Coat
  
  • Platelets
  • White cells
• Red Blood Cells

Question 14

What are some indications for RBC transfusion?

Answer 14

• Severe acute anaemia
• Uncorrectable anaemia
• Prepare patient for surgery or speed up recovery
• Sickle cell disease

Question 15

How are RBCs stored and transfused?

Answer 15

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

Question 16

How are platelets stored and transfused?

Answer 16

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

Question 17

What are the components of plasma?

Answer 17

• Fresh frozen plasma
• Cryoprecipitate

Question 18

What are the indications for FFP?

Answer 18

• Massive haemorrhage
• DIC with bleeding
• Prophylactic

Question 19

How is FFP used?

Answer 19

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

Question 20

What are the lab tests for FFP?

Answer 20

PT and APTT

Question 21

What is the lab test for cryoprecipitate?

Answer 21

Fibrinogen

Question 22

How is cryoprecipitate stored?

Answer 22

Frozen, allow 20 minutes to thaw

Question 23

How are patients grouped and screened?

Answer 23

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

Question 24

What is the direct Coombs test used for?

Answer 24

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

Question 25

What is the indirect Coombs test used for?

Answer 25

Cross matching

Question 26

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

Answer 26

37C

Question 27

What blood is usually available within minutes?

Answer 27

O- red cells (AB plasma)

Question 28

What bloods take time and are non-urgent?

Answer 28

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

Question 29

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

Answer 29

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

Question 30

What should decision to transfuse be based on?

Answer 30

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 31

How is prion disease transmittable?

Answer 31

By blood transfusion from early in the disease

Question 32

How should transfusion reactions be managed?

Answer 32

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

Question 33

What is sensitisation in rhesus disease?

Answer 33

Development of maternal anti D antibodies

Question 34

Does IgG cross the placenta?

Answer 34

Yes

Question 35

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

Answer 35

* Positive direct antiglobulin test * Jaundice * Anaemia

Question 36

How is HDN prevented?

Answer 36

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

Question 37

What is the treatment for HDN?

Answer 37

* Careful monitoring * Antibody titres * Doppler ultrasound * Intrauterine transfusions