Blood Transfusion Part 1 and 2 Flashcards Preview

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Flashcards in Blood Transfusion Part 1 and 2 Deck (23)
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What type of blood donations can you give?

1. whole blood
2. apheresis:
- platelets
- plasma
- plasma and platelets
- double red cell


What requirements does the Australian Red Cross Blood Service have for good donations?

- healthy
- 16-70
- >50kg
- no recent pregnancy, IV drug use or overseas travel


What are some of the rejection criteria of the Australian Red Cross Blood Service for blood donations?

- heart condition
- pregnancy
- anaemia
- tattoos
- iv drug use
- risky sexual behavior
- UK between certain dates (mad cow)


What components of blood are separated from a centrifuge?

Plasma products:
- cryoprecipitate
- cryodepleted plasma (minus clotting factors)
Buffy coat:
- white blood cells
- platelets


Why don't the Anti-A and Anti-B antibodies from donor blood go into recipients blood and attack the recipients blood?

Separating blood allows to separate red blood from antibodies, so the recipient won't receive the donors antibodies as well.


What is used to replace missing or low levels of proteins in blood?

Fresh frozen plasma


How do you store different blood components and for how long?

- RBCs in fridge for 42 days
- Platelets at room temp for 5 days
- Fresh frozen plasma below -25 for 12 months.

SO ALWAYS check the best before date.


What are the two types of grouping used to check AB status?

1. Forward grouping – take patients RBC’s and mix them with anti-serum which will react with antigens present on the RBCs. Determines directly what antigens are present on your RBCs.

2. Reverse grouping – take the patients plasma and mix it with commercial RBC’s to see what antibodies are in the patient’s plasma. Determines antigens INDIRECTLY by working out what antibodies are present.


What is the method of checking Rh status?

Forward grouping only:
Patient blood mixed with anti-D serum which contains antibodies against RhD.
- positive – agglutination observed
- negative – pellet observed


What method is used for both forward and reverse grouping?

Gel-column technique


How do you classify adverse blood transfusion events?

- Immunological or non-immunological
- Acute (24 hrs) or delayed

a) Acute Immunological:
- hemolytic transfusion reactions
- febrile non-hemolytic transfusion reactions
- allergic reactions (i.e. hives)
- transfusion-relation acute lung injury

b) Acute Non-Immunological:
- cardiac overload
- sepsis
- massive transfusion complications
- non immune mediate haemolysis (physical/chemical destruction of blood)

c) Delayed Immunological:
- formation of alloimmune red cell antibodies
- delayed haemolytic transfusion reaction

d) Delayed Non-Immunilogical:
- iron overload
- fever
- jaundice
- lower than expected haemoglobin


What are the signs of mild and sever adverse events?

1. Mild – itching, fever, hives and rash – easily treated
2. Severe – breathing difficulties, high fever, shaking, low BOP, dark urine, aches and pains.


What are the most COMMON adverse events and what are the most SERIOUS?

Most common adverse events:
- fever
- chills
- urticarial (hives)

Most serious:
- acute haemolytic transfusion reactions
- delayed haemolytic transfusion reactions
- bacterial contaminants of blood products


What are some contributing factors that affect adverse events?

- individual patient characteristics (i.e. age, if they are regularly transfused)
- blood component
- equipment (contamination)
- concomitant medications and IV fluids
- procedures. i.e. clerical errors


What are the steps in a haemolytic reaction?

1. patient antibodies coat donor RBC via surface antigens.
2. IgM antibodies activate the complement cascade
3. Formation of membrane attack complex
4. Agglutination of hemolysis of donor cells
5. Cytokine release (i.e. TFN) results in chills, rigors, dyspnea (shortness of breath), chest and/or flank pain and shock.
6. Haemoglobinuria, DIC, raised bilirubin and renal failure
7. Potentially death

NOTE: you can land up bleeding to death. Although a mismatch causes clotting, you eventually use up all of your clotting factors and then just bleed everywhere.


How do you treat a haemolytic reaction?

- fluid resuscitation to support circulation and maintain renal cortical perfusion
- airway support if require
- BP support if required


What are the most common causes of mismatches?

Most common causes of mismatches:
- patient’s blood has not been analyzed properly
- clerical errors
- incorrect labeling of blood samples/donations


How can you prevent mismatches?

- double checking clerical records
- Coombs test: mix some of donor and patient blood to see if there are any signs of reaction
- before transfusion, check that you have the right blood AND patient


What viruses need to be tested for in donor blood?

- HTLV – Human T-Cell lymphotrophic viruses
- Hep B
- Hep C
- WNV – West Nile Virus
- Parvovirus B19


What are the 2 types of tests used to determine if certain viruses are present in donor blood?

1. Serological – tests for exposure, antibody. Get samples from body fluid. BUT there is an eclipse phase. Then comes infectious phase, but to begin with although there are antibodies there aren’t enough to be detected. In total, the window period is how long it takes before you can detect it.

2. Nucleic Acid Testing (NAT) – rests for active infection, detects viral nucleic acids, get samples from site of infection. You can detect it earlier than serological. Drops window period significantly so decreases risk hugely.


What are the symptoms of bacterial sepsis?

- rigor
- fever
- severe chills
- hypotension
- tachycardia
- nausea and vomiting
- circulatory collapse
- DIC in severe cases (Disseminated Intravascular Coagulation) – can be fatal.


What are the possible sources of bacterial infection during blood transfusion?

- skin
- bacteraemic donor
- contamination from environment
- contamination during preparation process
- contamination of ports


How can you minimise bacterial contamination from blood transfusion?

- first 30mls diverted away
- visual screening of blood
- screening of donors
- ensure aseptic technique
- ensure cleaning of labs, wards, water baths
- don’t use expired products
- apheresis platelets have less risk compared to pooled platelets (apheresis requires only one donor)

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