5: Blood transfusion Flashcards
Blood donors must be ___.
healthy
so healthy weight, not anaemic, not infected with stuff, fully health screened
How long can RBCs be stored for?
35 days
How long can fresh frozen plasma (FFP) be stored for?
3 years
How long can platelets be stored for?
7 days
What does FFP contain?
Clotting factors
Different individuals have different blood ___.
blood groups
Which blood group system is coded for by chromosome 9?
ABO system
What is a blood group?
Antigens expressed on the surface of red blood cells
36 different types, inherited from parents
What is Landsteiner’s Law?
If you LACK an A or B antigen, antibodies to A or B antigens will be found in your blood from birth
What type of antibodies act against A and B antigens?
Anti-A IgM antibodies act against cells with B antigen
Anti-B IgM antibodies act against cells with A antigen
What do anti-A and anti-B antibodies cause?
Haemolysis of red blood cells with the corresponding antigens
What antibodies are produced by patients with blood group
a) O
b) A
c) B
d) AB?
a) Anti-A and Anti-B
b) Anti-B
c) Anti-A
d) None
You produce antibodies for the antigens you DON’T have
What is the next important blood group system after ABO?
Rhesus system
What is the genotype of a
a) Rhesus positive (Rh+)
b) Rhesus negative (Rh-) patient?
a) DD or Dd
b) dd
What happens to RhD negative patients if they are exposed to RhD positive blood?
Transfusion reaction
Haemolytic disease of newborn
link back to obstetrics
What are the two important blood group systems you need to know?
ABO system
Rh system
What is the name of the process which involves determining the blood group of a person by adding antibodies to a sample of blood?
Cross matching
Before receiving blood transfusions, patient ___ ___ must be identified.
blood groups
What is agglutination?
Clumping of red cells
because antibodies can bind to more than one red cell, bringing them together
Some antibodies don’t cause agglutination because they only have one / two binding sites.
How is this problem overcome?
Anti-human globulin
protein which binds to the ANTIBODIES, cause agglutination
Blood used for transfusions needs to be ___ with the patient blood group and antibodies.
compatible
the process of finding out if this is the case or not is called ‘cross matching’
In which situations is a blood transfusion indicated?
Symptomatic anaemia
Major haemorrhage
Under which haemoglobin concentration is a blood transfusion indicated?
< 70 g/L
Under which haemoglobin concentration is a blood transfusion indicated for patients with cardiac disease?
< 80 g/L
In which situations is a platelet transfusion indicated?
Thrombocytopaenia +/- bleeding
Bone marrow failure
FFP contains clotting factors.
In which situations is an FFP transfusion indicated?
Rx bleeding or prevention of bleeding in patients with COAGULOPATHIES
Massive haemorrhage
Patients need to be correctly ___ at each step of requesting a blood transfusion.
identified
What does group and screen mean?
A check for patient’s ABO group and antibody status
What happens to incorrectly or incompletely labelled blood samples?
Rejection by lab
When should observations be carried out on a patient receiving a blood transfusion?
Before transfusion
15 minutes post-admin
60 minutes post-completion
What type of hypersensitivity reaction is a blood transfusion reaction?
Type II hypersensitivity
Antibody mediated
Which group of people are given anti-D injections?
Pregnant Rhesus -ve women who have Rhesus +ve babies
Because if they are exposed to baby’s blood through haemorrhage, prenatal testing etc., they can have a haemolytic reaction
How much blood is typically transfused at a time?
One unit
