Blood Transfusion Flashcards
what needs to be check to ensure blood donor safety
minimum criteria:
weight 50kg
Hb 135 for men, 125 for women
make sure not anaemic
donor selection questionnaire
contact details if become wells post donation
what is FFP
fresh frozen plasma
stored for 3 years
how long are rbcs stored for
35 days
how long can platelets be stored for
7 days (agitated to stop them sticking together)
what microbiological tests are done on the blood
HIV, Hep B, Hep C, Hep E, HTLV, syphilis
what is available from the transfusion lab
blood components: red cells, FFP, platelets, cryoprecipitate
blood products: anti D immunoglobulin, prothrombin complex concentrate (used in warfarin overdose)
blood products from pharmacy: IV immunoglobulin, human albumin, specific Ig (e.g. varicella immunoglobulin to be given to pregnant women)
which blood group is most important for transfusion, why
ABO- as red cell all have antigens on cell surface depending on ABO genes, those antigens not present will have corresponding antibody in circulation which causes haemolysis of red cells with them
what determines ABO blood group
gene on chromosome 9
A and B genes code for transferases which modify precursor called H substance on red cell membrane
depending whether you are A B or O alters the structure of substance H
A and B are dominant over 0 and are co dominant with each other
O is silent
O adds no sugar
A and B add different sugars
what is the most common ABO type
O (47%) then A (42%) B (8%) AB (3%)
what antigens are present on group A red cells
A
what antigens are present on group B red cells
B
what antigens are present on group AB red cells
A and B
what antigens are present on group O red cells
neither
what is the genotype and phenotype of the ABO groups
phenotype- which antigens are detected (=which ABO group you are)
genotype- which genes are present
what are the genotypes for each ABO group
group O- OO
group A- AA or AO
group B- BB or BO
group AB- AB
how many ABO genes do you get from each parent
one
what antiBODY will you have if you are group A
B
what antiBODY will you have if you are group O
A and B
what antiBODY will you have if you are group AB
neither A nor B
what antiBODY will you have if you are group B
A
who can donor O blood be given to
everyone (no sugar, no antigens)
who can donor A blood be given to
A and AB
who can donor B blood be given to
B and AB
who can donor AB blood be given to
AB
what blood can O group people receive
only O blood as they have no A or B antiGENS
is it more common to RhD positive or negative
85% positive
what is the genetics of RhD blood groups
2 alleles D and d
inherit one from each parent
d is silent (will NOT have a D antiGEN, will have anti D antibody)
what genotypes are the RhD blood groups
RhD+ = DD or Dd RhD- = dd
what diseases are RhD groups responsible for
transfusion reactions haemolytic disease of the newborn (very immunogenic, small amount of blood creates lots of antibodies)
who should avoid D antigen (RhD+ blood) in transfusion
RhD -ve patients
what blood should you give RhD-ve patients
RhD-ve blood
what is the onset of transfusion reactions
ABO incompatibility= immediate reaction (IgM)
RhD incompatibility= delayed reaction (IgG)
how common are transfusion reactions
1% will have reaction
what are the aims of pre transfusion testing
identify ABO and RhD group
identify presence of clinically significant red cell antibodies (previous blood exposure that has resulted in antibody formation)
allow selection of blood
how is ABO grouping done
anti A, anti B and anti D Antisera (IgM reagent) (identifies antigens on red cells, causes agglutination)
reagent red cells of group
A and B (with known antigen specificity- if person has antibodies will get agglutination- clot) (addition of anti-human globulin facilitates agglutination)
what is the indirect antiglobulin test
uses reagent red cells, patient plasma and antihuman globulin (coombs reagent)
agglutination indicates antibodies to the reagent red cells
what in general does agglutination mean
blood is incompatible for transfer
what are the indications for red cell transfusion
symptomatic anaemia (Hb <70) major bleeding
what procedure should you follow for transfusions
transfuse a single unit and then reassess patient
always think of alternatives
what are the indications for platelet transfusion
prophylaxis in patients with bone marrow failure and very low platelets
treatment of bleeding in thrombocytopenic patient
prophylaxis prior to surgery/ procedure in thrombocytopenic patient
what are the indications fr FFP transfusion
bleeding in patient with coagulopathy (PT ratio >1.5)
prophylaxis prior to surgery in patient with coagulopathy (PT>1.5)
management of massive haemorrhage
transfuse early in trauma
give 50ml/kg
(used mostly to replace clotting factors, contains factors 1-12), correct PT and APTT ratio)
who is CMV -ve blood used in
pregnancy and neonates
how long is the sample for transfusion valid for if you have never been transfused or have not been transfused within the last 3 months
7 days
how long is the sample for transfusion valid for if you have been transfused or pregnant in the last 3 months
3 days
how should you lable blood samples
NEVER PRE LABLE
name, ward, gender
DOB, date and time of sampling, CHI number
signature
how should a patient be monitored during transfusion
within 60 mins before blood is commenced
obs at 15 mins
obs within 60 mins of completion
what should you watch out for during transfusion
pyrexia, rash, hypoxia
any adverse reactions stop transfusion and contact haematology reg
assess patient (can restart transfusion if mild reaction, may need to slow rate)
what are the signs and symptoms of acute transfusion reactions
often happen in early transfusion
sy- chills, rigors, rash, flushing, feeling of impending doom, collapse, loin pain, resp distress
si- fever, tachycardia, hypotension, tachypnoeia
what management for all transfusion reactions
stop transfusion abcde re check compatibility tag against patient details and inspect for evidence of contamination document event in notes contact transfusion lab
what should you do in severe/ life threatening reactions
(evidence of life threatening airway/ circulatory problem/ wrong component transfused/ bacterial contamination)
seek senior help
resus
return component blood to transfusion lab for analysis
which type of acute haemolytic transfusion reaction (AHTR) is most dangerous
ABO incompatible
causes INTRAvascular haemolysis of transfused cells
what causes an AHTR
binding of IgM anti A or B antibodies to antigens on donor blood = complement activation and lysis of transfused cells
- inflammatory cytokines (complement, kinin, coagulation systems) released
- shock, increased vascular permeability, DIC, renal failure
- often fatal
what is the clinical management of AHTR
stop transfusion return unit to lab oxygen, fluids repeat transfusion samples bloods for FBC, coag screen, renal function, haemolysis measures, blood cultures
what does the lab do after an AHTR
repeat ABO and RhD of pre and post transfusion samples
direct antiglobulin test (antibody bound to donor cells- shows recipient imune system fighting it)
repeat cross match
send remains of unit for culture
what are the ddx for an severe ATR
AHTR
bacterial contamination of blood component
what are the clinical features of a transfusion associated circulatory overload (TACO)
resp distress within 6 hours of transfusion (pulmonary oedema due to increased blood volume, pulmonary infiltrates)
raised BP
raised JVP
+ve fluid balance
what are the risk factors of TACO
elderly cardiac failure low albumin renal impairement fluid overload
what is the management for TACO
oxygen + supportive care diuretics consider slowing rate of transfusions consider diuretic with further transfusion only transfuse minimum volume required
what is a mild ATR like
Isolated temp rise >38 and rise of 1-2 degrees or rash only
what is the management for a mild TR
continue transfusion, consider slowing rate
close monitoring
consider paracetamol/ antihistamine
what can cause a mild TR
febrile non haemolytic transfusion reaction (Tx paracetamol)
mild allergic reaction (rash/ itch, commoner with plasma rich compenents, Tx= antihistamines)
what is a delayed haemolytic transfusion reaction
delayed immune response to red cell antigen- usually IgG Positive DAT (direct agglutination test) Extravascular haemolysis 5-10 days post transfusion
Transfused cells destroyed
Hb may drop, raised bili, LDH
Positive DAT and detection of alloantibody
is viral transmission common
no
what are the signs of a severe transfusion reaction
oedema
circulatory collapse
difficulty breathing
who needs irradiated blood products
previous hodgkins lymphoma previous purine analogue chemo anyone receiving HLA selected platelets (more closely matched to patient, more likely to cause GVHD) intrauterine transfusions stem cell transplant patients
who needs CMV negative blood
foetal transfusions
babies up to 4 months
pregnant women (not needed in delivery)
do you need to give HIV positive patients on retroviral Tx irradiated/ CMV negative blood
no, will likely also be CMV positive
do transplant patients need special blood
no, most immunosuppressants don’t carry special transfusion risks
what are the alternatives to transplant
IV/oral iron if IDA tranexamic acid (can also be use for surgery) or coil if menorrhagia B12/folate if megaloblastic anaemia cell salvage if surgery pre op anaemia check and treat
who could you maybe give RhD +ve blood to if they were RhD-
men or people past child bearing age
how must you identify patient for transfusion
positive identification: ask them to ask name and DOB
check with other HCP that it matches wristband and blood products
how many blood samples from patient do you need before transfuse
2 separate ones (can be historical or from different venepuncture sites)
how long is the transfusion window for one pack of blood
4 hours
what can you give for a mild transfusion reaction
paracetamol
piritin
slow infusion rate
if a large transfusion is anticipated to be required what could be prepared for this
blood warmers
cell salvage
prior group and save if possible
what groups are the universal donor and acceptor
O universal donor
AB universal acceptor
what can cause delayed transfusion reactions
infections (bact, fungal, crion - CJD), iron overload, GVHD, purpura
what does oozing at venepuncture site suggest
acute transfusion reaction
what does a febrile non haemolytic reaction look like
fever, shivering 1/2 - 1 hour after transfusion
what x-ray sign in TRALI
white out
what signs in fluid overload
dyspnoea, hypoxia, tachycardia, raised JVP, basal creps
what antibodies are tested for
any that cause clinically significant reactions e.g. anti k
when is a blood transfusion indicated
Hb <70g/L
other comorbs e.g. bone marrow prob, COPD
symptomatic anaemia
what extra precautions for transfusion in HF patient
transfuse slowly with diuretics and assess repeatedly for fluid overload
what does irradiated blood not have
donor lymphocytes (why it prevents GVDH as these establish immune system in recipient marrow)
when would you transfuse platelets
<20 or <100 for surgery
when would you transfuse FFP
clotting defects, warfarin OD, liver disease, TTP
when would you transfuse albumin
hypoproteinaemic patient (liver disease, nephrosis) with fluid overload
what type of rash can occur in ATR
urticarial
what can cause a mild TR
febrile non haemolytic
mild allergic
what can cause a severe TR
ABO incompatibility- acute haemolysis
bacterial contamination (more common in platelets)
IgA deficiency (anaphylaxis to IgA in red cells)
TACO and TRALI (both present with resp distress)
