Blood Transfusion Flashcards

Question

what are the uses of platelets?

Answer 1

* Massive haemorrhage - Keep platelet count above 75x109/l * Bone marrow failure - platelet count \<10-15 × 109/litre, or \<20 × 109/litre if additional risk, e.g. sepsis * Prophylaxis for surgery - Minor procedures 50x109/l;, More major surgery 80x109/l; CNS or eye surgery 100x109/l * Cardiopulmonary bypass - use only if bleeding

Answer 2

1 unit from 1 unit of blood Stored frozen, allow 30 minutes to thaw 1 unit of FFP for 1 bag of red cells

Answer 3

massive haemorrhage (use in 1:1 ratio?) DIC with bleeding ‘prophylactic’ (if expected to bleed)

Answer 4

Cryoprecipitate, also called cryo for short, is a frozen blood product prepared from blood plasma. To create cryoprecipitate, fresh frozen plasma thawed to 1–6 °C is then centrifuged and the precipitate is collected. 1-2 pools if fib \<1.0g/dl (1.5g/dl) Stored frozen; allow 20 minutes to thaw Cryoprecipitate – prescribe less, made from gradually thawing FFP, fibrinogen concentrate

Answer 5

Blood sample (EDTA) Two sample policy (need to samples to avoid ABO mistakes) Group and Screen/Save Cross matching

Answer 6

(Lab check) ABO and RhD type Checked against historical records Screen for allo-antibodies in serum If patient is A, if you add anti-A monoclonal antibodies to them the red cells clump together meaning there is A antigen on surface of red cells If you add B as seen in the next column, red cells still dispersed and no reaction In anti-AB you see the red cells are all clumped together You also do a reverse group where you add the patients serum to the cells When you add the serum form that patient to A cells, it doesn’t contain anti-A and there is no agglutination But when you add the patients serum to B cells the patient does have anti-B and there is agglutination

Answer 7

Trying to detect antibodies on the surface of red cells Blood grouping is IgM antibodies – they are multivalent If IgG on surface of red cells then they wont clump together Because it is bivalent it will link the red cells together and cause a agglutination so the test can pick up IgG on the surface of red cells Positive = antibody on surface of red cells

Answer 8

Direct: - autoimmune haemolytic anaemia - passive anti-D - haemolytic transfusion reactions Indirect: - Cross matching Indirect coombs test = when you are adding an external antibody to see it binds the red cells which you then cross link and we use this in cross matching

Answer 9

Finally we screen sample you sent in blood bank for alloantibodies They are quite rare If reaction, like in this case, against cells 1, 2, 3 and 8 then you can say this patient has an anti-D and you should choose D negative cells to transfuse

Answer 10

Mother can develop antibodies against foreign antigens that are carried by their babies that have been encoded by paternal alleles RHD system is the most important 15% of mothers are RDH- and if the father is RDH+ which most men are, then they are at risk of developing the disease If red cells leak across the placenta in pregnancy or particularly at birth then the mother will pick up the foreign cells and form an antibody It’s a protein and usually an IgG and IgG crosses the placenta The IgG in subsequent pregnancies can cross the placenta and cause alloimmune haemolysis in the baby, the baby then become anaemic and can get cardiac failure and die

Answer 11

Anti-D immunoglobulin after birth The injection will destroy any RhD positive blood cells that may have crossed over into your bloodstream during the delivery. This means your blood won't have a chance to produce antibodies and will significantly decrease the risk of your next baby having rhesus disease.

Answer 12

All RhD mother are screened throughout pregnancy for the development of antiD At around 28 weeks of pregnancy of pregnancy, all RhD negative mothers are injected with antiD so in the latter stages of pregnancy there is less chances of developing antiD subsequently and likewise at birth every mother should be picked up that is RhD negative and if they have a RhD positive baby they should have further antiD to prevent problems in future pregnancies

Answer 13

Prevention using prophylactic anti-D: ## Footnote - Sensitising events - Routine at 28/40 Treatment by careful monitoring: - Antibody titres - Doppler ultrasound - Intrauterine transfusions Neonatal alloimmune thrombocytopenia (NAIT) similar process for platelets - If baby born with low platelet count at birth, one of the first things to think about is there is an antibody present that we can pick up on our tests