Blood transfusion Flashcards
What are the blood groups?
ABO groubs
On rbc membrane-antigens that have functions
Use to recognise foreign Rbc in body
A and B have a same H antigen STEM-on which 1 residue is added
O people have only H stem. AB have 50/50
What are the genes responsible for the ABO groups?
Antigens are determined by the genes- A genes cause of a N-acetyl glalctosamine-and gives that glycoprotein B-is for enzyem that adds galactose AB-co-dominant O genes are recessive-add nothing on
When do AB vs ABO groups appear? WHat types of AB are there?
Have them from birth-AB for whatever you lack
ALways IgM-these are full blown AB-activate complement (cause heamolysis of RBC)-
ALso causes agglutination of the RBC
But makes the grouping easier (using agglutinatin-form clump in tube
What are the most common blood groups?
A-42%
B-8%
O-47%
AB-3%
Which group can recieve and give to which?
O can give to anyone (but has anti A and B)
AB can recieve anything
A-only A (or recieve O)
B-only B (or recieve B)
How do you test for a blood group in hopsital?
Put blood with a known AB (anti A or B)-if it clumps therefor IgM anti-A/B react and it has it if A-A If B-B If A AND B-AB if nothing- O
What is a rh group?
Very important-immunogenic
RhD-(positif=RhD DD or Dd, negative=dd)
positive has D antigen
If RhD+ people are presented with D-no matter-no AntiD anytime
If RhD- poeple are presented-can cause a Anti-D reaction
these are not present from birth in RhD- patients-need first contact (usually want to prevent that)
What AB class react with D antigen? When does it matter the most
IgG-cause heamolysis of RBC
but will be very delayed (10days)-cant activate complement imediatly-happens only once they reach the spleen
Can be dangerous-if already sick
In pregancy-if RhD- mother has anti-D and in her future prgenancy, kid has D-antigen-then D AB cross placenta and heamolysis-can cause brain damage and death (from heart failure) (bilirubin being high)
What other Red cell groups exist? How significant are there?
Tons of other ones-about 12 have relevant heamolytic AB reactions
Most of the other antigens of RBC do not elicit very bad reaction
Cannot match all these-so mainly RhD and ABO–so really then just test plasma to see if theyve developped antigen (most people dont)-test it before versus donors blood
What is contained in a bag of a blood donor?
1unit (pint)-has anticoagulant
Split-Red cells are concentrated and removed (immediatly)
Plasma is removed (avoid fluid overload/or need clotting factors)
Platelets and White cells also seperated-for others
How can plasma be conserved and treated?
usually-frozen (classic to keep)
Cryprecipitate (Frozen then thawed in fridge overnight-get a concentrate of Fibrinogen and FVIII)
Finally-mega pooling and then use fractionating column and get tons of thigs out of it
How are red cells conserved?
1 unit is from 1 donor
Only keep 5 weeks at 4C-
Blood giving set (stand and bag)-removes clumps/debris
Rarely frozen-only for rare blood types-but poor recovery on thawing (1/3 die)
What is Fresh Frozen plasma? How is it stored?
1unit-300ml
Shelf life-2/3 years
Must thaw slowly over 30mins (but cannot too fast or else cook)-give within 1h
Need to know blood group because the plasma contains all the ABs againt the other groups
When would you use FFP?
If bleeding and have abnomral coagulation tests (PT/APTT)-monitor response
Reversal of Anticoagulants for urgent surgeries-if PCC
(warfarin 2-7-9-10
Other occasionally-inherited deficiencies
NEVER TO REPLACE FLUID LOSS
What is cryoprecipitates? How is it used?
To make 1-need 10 patients
In massive bleeding-fibrinogens tends to drops
And rare hypofibrinogeamia
How are platelets stored?
need 4 donors to make 1 unit-store at room temperature-but only 5 days shelf life
No need to cross match but better to keep group-or else they die a bit faster
Keep plasma a bit around the Platelet-might contain a bit of Anti-ABO-
But can cause RhD sensitisation
When would you give platelet transfusion
Heamatology patients with bone marrow failures-intense chemotherapies Or massive bleeding or DIC If platelets low and need surgery If patient on anti-platelet drugs 1 pool usually is all necessary
What products can be obtained by plasma pooling and fractionation?
Factor VIII and IX - for heamophilia (but recombinant exist now)
Immunoglobulins: (Im-specific (tetanus, rabies), General soup that everyone has-for very sick patients (can also help AID patient
Albumin-4.5%-if losing water and protein-need it back in for osmotic pressure-can be result of severe burns
20%-liver/kidney issues-pouring proteins out-stronger dose
What are the precautions taken with blood donors?
Want to keep the recipient safes-
If known blood infection (like hepB)-denied
High risk behaviours are also prohibited (because no test can pick up everything)-thats what the questions are for
=> a few are systematically tested, like HTLV, etc
Also want to avoid harm to donor (if they have heart issues, etc)-avoid
Questions cannot always be taylored to individuals-like IV users (just exclude them for a while-testing cant always be relied on)
Prion disease-vCJD-4 cases from blood donors in UK (ever)-but as precaution-all plasma pooled for fractionation are from USA
All blood components have WBC filtered out
