Blood Transfusion Flashcards
Describe the processing and testing of blood after donation
- Blood centrifuged to separate into component parts
- Sample checked for HIV, Hep B, C & E, HTLV, Syphilis etc
- Platelets, FFP & RBCs separated & stored separately
Name the 4 blood components available from the transfusion lab and state their main uses
- RBCs - symptomatic anaemia, major bleeding
- FFP - replacement of coagulation factors in patients with coagulate who are bleeding or undergoing surgery or in patients with massive haemorrhage
- Platelets - thrombocytopenia treatment or prophylaxis (depending on cause)
- cryoprecipitate
Name other blood products available from
A) the transfusion lab
B) the pharmacy
A) Transfusion lab
- Anti-D immunoglobulin
- Prothrombin complex concentrate
B) Pharmacy
- IV immunoglobulin
- Human albumin
What determines blood group
RBC antigens
Describe the ABO system and the 4 groups
- The ABO gene on chromosome 9
- Receive one copy from each parent
- Gene A and B are co-dominant, gene O is silent
- Group O, genotype OO
- Group A, genotype AA or AO
- Group B, genotype BB or BO
- Group AB, genotype AB
Describe Landsteiner’s law in the ABO system
If an individual does name have the A or B antigen then they must naturally have the A or B antibody I.e.
Group AB - have neither antibody, can be given any blood type
Group A - have B antibody, can be only given group A or O blood type
Group B - have A antibody, can be only given group B or O blood type
Group O - have A and B antibody, can only be given group O blood type
Group O - universal blood donor
Explain the clinical relevance of the ABO system when giving a blood or plasma transfusion
Blood has antigens in them so if an individual has the antibodies for that antigen then they cant be given it.
Plasma has antibodies in them so if an individual has the antigens for that antibody then they cant be given it.
Group AB
- Have both antigens & have neither antibodies
- can be given any blood type (as don’t have any antibodies)
- can only be given AB plasma (as have both A & B antigens)
Group A
- Have A antigen & have B antibody
- can be only given group A or O blood type (as have B antibodies)
- can only be given AB or A plasma (as have A antigen)
Group B
- Have B antigen & have A antibody
- can be only given group B or O blood type (as have A antibodies)
- can only be given AB or B plasma (as have B antigen)
Group O
- Have no antigens & have A and B antibody
- can only be given group O blood type (as have A & B antibodies)
- can be given any plasma (as don’t have any antigens)
What pre transfusion tests should be carried out on an individual
Indirect coomb’s (anti-globin) test
- Test for ABO & RhD group of patient
- Test for clinically significant RBC antibodies
Wet cross match or electronic confirmation of cross match
Describe the RhD system and its clinical relevance
Around 85% of the population are positive for RhD antigen.
For the 15% that are RhD antigen negative, they have Anti-D antibodies.
If they were to receive a blood transfusion from someone who has the RhD antigen they would experience a transfusion reaction.
RhD antigen and Anti-D antibody reaction is also responsible from haemolytic disease of the foetus & newborn.
Compare the uses of a direct vs indirect coomb’s (anti-globin) test
Direct coomb’s test - test for haemolytic anaemia
Indirect coomb’s test - prenatal & pretransfusion test
Name the 5 main acute transfusion reactions
- Allergy
- Acute haemolytic transfusion reaction
- Febrile non-haemolytic transfusion reaction
- Transfusion related acute lung injury (TRALI)
- Transfusion associated circulatory overload (TACO)
What causes a post transfusion allergic reaction, how does it present and how is it managed?
Aetiology
- Minor allergic reaction is thought to be caused by foreign plasma proteins
- Anaphylaxis can be caused by patients with IgA deficiency who have anti-IgA antibodies
Presentation
- Ranges from urticaria to angioedema and anaphylaxis
Management
- Stop the transfusion, give saline, adrenaline (in case of anaphylaxis), chlorphenamine, and hydrocortisone
What causes an acute haemolytic transfusion reaction, how does it present and how is it managed?
Aetiology
- Caused by giving an incompatible blood bag to a patient
Presentation
- Early signs include fever, abdominal pain, hypotension and anxiety
- Late complications include generalised bleeding secondary to DIC
Management
- Stop the transfusion, give saline, treat DIC
What causes a febrile non-haemolytic transfusion reaction, how does it present and how is it managed?
Aetiology
- Thought to be caused by antibodies reacting with white cell fragments in the blood product and cytokines that have leaked from the blood cell during storage
Presentation
- Presents with fever, rigors/chills, but patients are otherwise well
Management
- Slow the transfusion, give paracetamol
What causes a transfusion-related acute lung injury, how does it present and how is it managed?
Aetiology
- Non-cardiogenic pulmonary oedema thought to be secondary to increased vascular permeability caused by host neutrophils that become activated by substances in donated blood
Presentation
- Presents with pulmonary oedema and can cause acute respiratory distress syndrome (ARDS)
Management
- Stop the transfusion, give saline, treat ARDS and give supplementary oxygen as needed
