Blood Transfusions Flashcards
Why are there different blood groups?
Red cells express different antigens on their cell surface.
These can provoke antibodies.
There are 2 types of antigens A and B that are expressed in different combinations on certain cells.
What antigens/antibodies are present on Group A blood?
A antigen on its surface.
B antibodies in its plasma.
What antigens/antibodies are present on Group B blood?
B antigens
A antibodies in its plasma
What antigens/antibodies are present in group AB blood?
A and B antigens
But NO antibodies
What antigens/antibodies are present in Group O blood?
NO antigens
A and B antibodies
How can blood be transfused safely?
Group A - can get A and O
Group B - can get B and O
Group AB - can get A, B, AB & O.
Group O - can get O.
What is FFP?
Fresh Frozen Plasma.
Contains antibodies so is opposite to RBC transfusion.
How can FFP be transfused safely?
Group A - can get A and AB.
Group B - can get B and AB
Group AB - can get AB.
Group O can get A, B, AB and O.
What is Rh factor?
Protein that can be either positive (present) or negative (absent) on the surface of RBCs.
Rh + is most common type.
What is Anti D?
Antibody that RhD individuals make if they are exposed to RhD+ cells.
Can occur in transfusion or pregnancy.
Anti D can cause transfusion reactions or haemolytic disease of the newborn.
What is the blood tested for before it can be donated?
Behavioural screening - sex, travel, tattoos, age.
Tested for ABO and Rh blood groups.
Screened for Hep B/C/E, HIV, Syphilis.
Variably screened for HTLV1, malaria, West nile virus, Zika virus.
What are the products of Plasma?
Clotting factors
Albumin
Antibodies
What are the components of a Buffy coat?
Platelets White cells (leucocytes)
What are some indications for red cell transfusion?
To correct anaemia
Improve quality of life
Prepare patient for surgery to speed up recovery
Reverse damage caused by patients own RBCs e.g. sickle cell disease.
How do you store RBCs?
Stored at 4 degrees C
Transfuse over 2-4hours
1 unit increments = 5g/L
How do you store Platelets?
22 degrees C Shelf life of 7 days Transfuse over 20-30mins 1 dose of platelets = 4 pooled donors or 1 aphaeresis donor. 20-40.10 to the 9/L
How much platelets should you give?
Massive haemorrhage - keep count about 75x10(9)/L
Bone marrow failure - <10-15 x10(9)
Minor procedures 50X10(9)
Major surgery 80x10(9)
CNS/eye surgery 100x10(9)
Only use if bleeding during cardiopulmonary bypass.
How is FFP stored?
Stored frozen, allow 30mins to thaw.
1 unit from 1 unit of blood
When is FFP indicated?
Massive haemorrhage
DIC with bleeding
Prophylactic
How is Cryoprecipitate stored?
Source of fibrinogen
Stored frozen, 20mins to thaw.
1-2pools in fib <1.0g/dl
What is a group and screen?
A blood group and an antibody screen of a sample of blood to see what type the patient needs and whether they have any atypical antibodies in their blood.
What is a Coombs test?
Used to detect antibodies that attack the surface of your red blood cells.
Direct test - autoimmune haemolytic anaemia, passive anti D, haemolytic transfusion reactions.
Indirect - cross matching
What happens when a Rh - mum is pregnant with a Rh+ baby?
When mum come sin contact with foetal blood she starts to produce Anti D antibodies. These are IgG which can cross the placenta.
They then go onto attack the antigens on the surface of the baby’s RBCs.
Can result in Haemolytic disease of the newborn (HDN).
What are some signs of HDN at birth?
Positive DAT
Anaemia
Jaundice
