Blood Transfusion Seminars Flashcards
What are the types of blood donations you can give?
- whole blood
- apheresis:
- platelets
- plasma
- plasma and platelets
- double red cell
What are the requirements?
- healthy
- 16-70
- > 50kg
- no recent pregnancy, IV drug use or overseas travel
What are the rejection criteria?
- heart condition
- pregnancy
- anaemia
- tattoos
- iv drug use
- risky sexual behavior
- UK between certain dates (mad cow)
What are the components of blood?
Red blood (leucodepleted to avoid adverse reactions)
Plasma products:
- cryoprecipitate
- cryodepleted plasma (minus clotting factors)
Buffy coat:
- white blood cells
- platelets
Why do we only worry about the recipients antibodies, and not the donors?
Anti-A and Anti-B antibodies from donor are in the plasma fraction, so separating blood allows to separate red blood from antibodies, which means O can go to A, B and AB. We only have to worry about antibodies in recipient.
What are plasma products used for?
Low platelet count or dysfunctional platelets can lead to increased risk of bleeding, I,e, due to chemo.
Fresh frozen plasma used to replace missing or low levels of proteins in blood.
Cryoprecipitate contains clotting factors, so used with clotting disorders.
What storage is required for blood?
- 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.
How is AB status checked?
- 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.
- 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.
How is RhD status determined?
Only forward typing.
Patient blood mixed with anti-D serum which contains antibodies against RhD.
- positive – agglutination observed
- negative – pellet observed
What is the Gel-column technique?
Gel-column technique, which can do both forward and reverse grouping. RBCs will either float or sink. RBC’s can travel down the column, which is Swiss cheese like. But they can’t if there is agglutination, therefore they will stay at the top.
If control is at top, then the test is useless because it would be agglutinating regardless of exposure.
What is a crossmatch?
Mix RBCs from donor with the patient’s serum from the actual bag you are going to use, and there should be no haemolysis or aggulation or you might kill them.
- Abbreviated crossmatch
- Antiglobulin crossmatch – can detect the actual immune response specifically
If you don’t have time to check, best is O- and just hope for the best.
What is an adverse event in relation to a transfusion?
- Mild – itching, fever, hives and rash – easily treated
2. Severe – breathing difficulties, high fever, shaking, low BP, dark urine, aches and pains.
How are adverse events classified?
Classification:
- 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 most common adverse events?
- fever
- chills
- urticarial (hives)
What are the most serious adverse events?
- acute haemolytic transfusion reactions
- delayed haemolytic transfusion reactions
- bacterial contaminants of blood products