Blood transfusion Flashcards
what are the components of blood offered by the transfusion service
red cells
platelets
fresh frozen plasma
cryoprecipitate
how are blood components obtained
centrifuging anti-coagulated blood to separate it
one unit of the blood components comes from one/many donors
one
what are the blood products offered by the transfusion therapy
human albumin IV immunoglobulin human normal immunoglobulin tetanus, hep B etc immunoglobulins anti-D immunoglobulins prothrombin complex concentrates
blood products come from one/many donors
many
how is the safety of the blood ensured
exclude infective risk from donor - tonsillitis, flu etc
exclude risk of disease transmission - malignancy, neuro conditions of uncertain aetiology (MS)
donor encouraged to get in contact if they become ill
what are the 4 blood groups in the ABO group
group A (carry A antigen) group B (carry B antigen) group AB (carry A and B antigens) group O ( doesn't carry or B)
what antibodies will group O carry
A and B
what antibodies will group A carry
B
what antibodies will group B carry
A
what antibodies will group AB carry
none
what is the universal donor blood type
type O - no antibodies against this blood type
what is the universal recipient blood type
type AB - these people have produced no antibodies against blood
what is the least and most common blood types
least common - AB
most common - O
what type of antibodies are the naturally occurring ABO-antibodies
IgM (mostly)
some IgG
which chromosome has the genes which determine blood group
chromosome 9
out of the A, B and O genes, which are dominant/recessive
A and B are co-dominant
O is silent/recessive
what genotype gives the O phenotype
OO
what genotype(s) give the A phenotype
AA or AO
B is therefore BB or BO
what genotype gives AB phenotype
AB
which chromosome is responsible for determining Rh(D) protein
chromosome 1
genotypes that give RhD positive
DD or Dd
when can someone go from RhD negative to RhD positive
when exposed to RhD positive red cells:
pregnancy with RhD positive foetus
blood transfusion
develops antiD antibody
consequences of giving RhD positive blood to someone who is RhD negative
no issues on first transfusion - this is when they form the antibody
could cause delayed haemolytic transfusion reaction after further transfusions
what is the reaction called when antibody is introduced to corresponding blood cells
agglutination - cross links red cells
when is agglutination used in the laboratory
to determine someone’s blood type
what puts someone at risk for irregular antibodies (not naturally occurring ABO ones)
previous pregnancy
previous blood transfusions
indications for red cell transfusion
anaemia (if untreatable cause or life threatening)
acute blood loss
indication for frozen plasma
bleeding in surgery with liver disease and impaired coagulation
coagulopathy following massive transfusion
disseminated intravascular coagulation
indication for platelet transfusion
low platelets
symptoms of bleeding
underlying infection
risks of transfusions
immediate haemolytic transfusion reaction
delayed haemolytic transfusion reaction
febrile non-haemolytic transfusion reactions
urticarial reactions
circulatory overload
bacterial/viral infection
what is immediate haemolytic transfusion reaction
the transfusion of incompatible red cells (e.g. A donor to O recipient)
what happens when antibodies bind to RBCs in circulation
activates complement cascade, coagulation system and kinin system
what happens when complement cascade is activated
C3a and C5a activate the membrane attack complex - leads to rupture of transfused cells
increased vascular permeability
dilated vessels
release of serotonin and histamine (fever, chills, hypotension, hsock)
what happens when kinin system activated
activated by Factor XII
formation of bradykinin (dilatation and increased permeability)
hypotension
catecholamine release - vasoconstriction in kidneys
clinical features of immediate haemolytic transfusion reaction
pyrexia and rigors faint/dizzy tachycardia and tachypnoea hypotension headaches cyanosis
management of acute haemolytic transfusion reaction
stop transfusion
IV fluids
blood samples - FBC, coag, U+E, cultures
how long after transfusion does delayed haemolytic transfusion occur
5-10 days
what is febrile non-haemolytic transfusion reactions
recipient has anti-HLA antibodies which binds to residual white cells
clinical features of febrile non-haemolytic transfusion
rapid temp rise
chills/rigors
investigations if suspected febrile non-haemolytic transfusion reaction
look for HLA antibodies
double check red cells were compatible
management of febrile non-haemolytic reactions
if transfusion is non-urgent, stop and exclude more serious reaction
can give anti-pyretics (paracetamol) before transfusion as prophylaxis
risk factors for circulatory overload in blood transfusions
elderly
congestive cardiac failure
