Blood transfusions Flashcards
what happens to blood after someone has donated
centrifuged = separated into parts
how long are red cells stored for
at what temp
stored for 35 days at 4 degrees
how long is FFP stored for
at what temp
stored for up to 3 years at -30 degrees
needs to be thawed before usage
how long is platelets stored for
at what temp
stored for 7 days at room temp
bag is rocked (agitation)
think platelet life span is 7-10 days!
most blood donation products come from one donor only, which products come from a pool of donor blood
anti-D prothrombin complex IVIg human albumin Ig
which chromosome number determines ABO grouping
chromosome 9
what are the 3 allele options in ABO grouping
get one from each parent
A antigen
B antigen
no antigen (O = absence of A or B antigen)
which ABO alleles are co-dominant over the other
A and B are co-dominant over O
what is landsteiners law for ABO groupings
example for A, O and AB blood groups
clinical significance of this
if someone lacks an antigen (A or B or both) they will make the corresponding antibody in their own plasma
eg someone with blood type A (AA or AO) will have anti-B antibodies
eg someone with blood type O (OO) will have anti-A and anti-B antibodies
eg someone with blood type AB will have neither anti-A or anti-B antibodies
if you give someone blood with an antigen in it and they have the anti bodies = haemolysis
if you give someone with blood group A blood that is O what will happen
nothing - is compatible
if you give someone with blood group A blood that is AB what will happen
haemolysis
bc blood type A = has developed antibodies against B (anti-B)
if you give AB blood = anti-B will react against B antigens = haemolysis
% of population RhD +ve
85%
what alleles do you need to be RhD -ve
dd (2 copies of recessive d)
what do people with RhD -ve have that RhD +ve don’t
anti-D antibody (bc they DONT have the antigen)
is RhD +ve or -ve the ‘universal’ donor
why
RhD -ve
bc -ve has the anti-D antibody bc they lack the antigen
so if you give someone who is RhD +ve some RhD -ve blood they will be fine
but if you give someone who is RhD -ve some RhD +ve blood, they have anti-D antibodies = haemolysis against D antigens in donor blood
how do you do ABO grouping (2 stages)
use anti-A, anti-B and anti-D reagents (antisera) to see which antigens are present on the RBCs
indirect antiglobulin test - essentially same but back to front, test patients plasma (will contain/not anti-A/B/D etc) on RBCs with known antigens
in ABO testing if antigen is present on RBC and you give the antibody (anti-A etc), what will happen
agglutination (clumping)
indirect antiglobulin test for someone with blood group A
test their plasma (should contain anti-B) against RBCs with B antigens on them
= should agglutinate (clump together)
for indirect antiglobulin test in ABO testing, what chemical do you need to use to facilitate agglutination
anti-human globulin (AHG)
indications for blood transfusion (2)
symptomatic anaemia Hb<70g/L
major bleeding
indications for FFP (fresh frozen plasma) transfusion
MUST HAVE BLEEDING and coagulopathy (PT ratio >1.5)
cause of acute hemolytic transfusion reaction (2)
ABO incompatilbility - wrong patient
bacterial contamination
where does the haemolysis occur in acute transfusion reactions
is it IgM or IgG mediated
immediate reaction = intravascular
IgM
(bc iMMediate)
<5mins of transfusion
fever
flush
feeling of impending doom
acute haemolytic transfusion reaction - ABO incompatibility or bacterial contamination
management of acute haemolytic transfusion reaction (3)
STOP transfusion
ABCDE
blood cultures for sepsis (bacterial contamination)
30 mins into transfusion elderly raised JVP SOB pitting oedema
transfusion associated circulatory overload (TACO)
management of transfusion associated circulatory overload (TACO) (2)
diuretics (furosemide)
transfuse slower
current transfusion
fever
rash
febrile non haemolytic transfusion reaction (mild, acute)
management of febrile non hemolytic transfusion reaction (2)
paracetamol for fever
transfuse slower
PMH allergy
current transfusion
mild urticarial rash
SOB
allergic transfusion reaction
can also present as severe anaphylaxis
FFP transfusion
SOB but normal JVP
transfusion associated lung injury
no fluid overload like TACO
anti-leukocyte reaction to FFP
management of allergic transfusion reaction (4)
adrenaline
anti histamine (chlorampheniramine)
salbutamol (for SOB bronchoconstriction)
steroids
complication of chronic transfusions eg thalassaemia
iron overload - need iron chelating drugs
5-10 days after transfusion
jaundice
delayed haemolytic transfusion reaction
where does the haemolysis occur in delayed transfusion reactions
is it IgM or IgG mediated
extravascular - bc has had time to move from circulation (immediate reaction = intravascular)
IgG mediated (bc iMMediate = IgM)
what electrolyte abnormality can out of date blood cause
hyperkalaemia
