blood transfusion Flashcards
What do groups A and B have attached?
- extra sugar reside
what does A gene code for? what about B gene?
A gene: N-acetyl galactosamine
B gene: Galactose
describe structure of group O
just fucose stem, no extra sugar
what is the universal donor/receiever?
OO- = donor AB+ = receiver
what antibodies are found in a person’s blood?
- person has antibodies against any antigen NOT present on their own red cell
- e.g. patient with group A, have antibodies against group B
what is the antibody that reacts against miss-matched blood?
- IgM
- is a complete antibody
- when it reacts it causes a full complement cascade and haemolysis of red cells
- can be fatal
- also causes agglutination of red cells
how is a person’s blood tested?
- by reaction it with known anti-A and anti-B reagents to test group
- donor of same group then selected and blood crossed matched to be sure (check for agglutination)
What are RH blood groups?
- RHD positive or negative
- having D-antigen on RBC
- -ve have no D antigen on RBC
- RhD is co-dominant
- 85% are RhD+, 15% are RhD-
What are anti-D antibodies?
IgG
not as bad as IgM
When can people who are RhD- make D antibodies after exposure to RhD antigen?
- by transfusion of RhD+ blood
- in women if pregnant with RhD+ child
what are the implications of transfusing RhD+ blood to RhD- people?
- Pt must have RhD- blood in the future otherwise anti-D antibodies they have made from 1st transfusion would react
= delayed haemolytic transfusion reaction
what are the implications of a mother having RhD- blood anf the baby has RhD+?
- RhD- mother has anti-Antibodies made post transfusion
- in next pregnancy, has a child that is RhD+
- mothers IgG antibodies will cross placenta and attack child’s RBCs
= haemolytic disease of new born
how do you avoid both of these?
- transfuse blood of same RhD froup as pt
- can give RhD- to any pt
- O- blood used in emergency
when you centrifuge blood, what is found at different levels?
- RBCs at bottom
- platelets middle
- plasma top
how are red cells stored? how many units from a donor
- stores for 5 weeks at $C
- not normally given frozen as poor recovery upon thawing
- 1 unit/donor
What is the storage of FFP? how much/ donor?
- 1 unit/ donor
- dose is 3 units
- stores for 2 years at -30C
- thaw 20-30 mins before use
what are the implications for use of FFP?
- bleeding and abnormal coagulation tests results (PT and APTT)
- reversal of warfarin for urgent surgery
What is cryoprecipitate formed from? what does it contain?
formed from frozen plasma thaw residue
contains fibrinogen and F8
what is the storage and dose of cryoprecipitate?
- stored at -30C for 2 years
- 1 dose from 10 donors
when is cryoprecipitste used?
- given for massive bleeding
- hypofibrinogenaemia
how many donors does it take to get platelets? how is it stored?
- 1 pool from 4 donors or from ` donor by apheresis
- stored at 22C but constantly agitated for 5 days only
what are the indications of use for platelets?
- bone marrow failure
- massive bleeding
- DIC
- surgery (pt has low platelets)
- cardiac bypass and pt on anti-platelets
what are the different fractioned products?
- F8/9
- immunoglobulins
- albumin
what must all blood be tested for?
- Hep B/C
- HIV
- HTLV
- Syphilis
- CMV
what is Prion disease? How is it avoided?
- vCJD
- can be transmitted by blood transfusions
- as a precaution all plasma pooled to make fractioned products obtained from USA
- all blood components have white cell filtered out (white cells essential for uptake of vCJF prion into brain)
