Blood transfusion Flashcards
(29 cards)
RBC:
- storage temperature
- shelf life
- if removed from controlled storage when does it need to be used?
temp: -2 to 4 degrees
shelf life: 35 days
If removed for more than 30mins have to use, have to use within 4hours
Platelets:
- storage temperature
- shelf life
- if removed from controlled storage when does it need to be used?
Temp: 22degree and continual agitation
Shelf life: 5 days
If removed has to be transfused within 1 hour
Fresh frozen plasma:
- storage temperature
- shelf life
- if removed from controlled storage when does it need to be used?
Temp: -30degrees
Shelf life: 2 years
Thawed prior to transfusion and transfuse within 4 hours
What antigen is on the RBC and what antibodies are present in the blood of someone with blood group: A B AB O What type of antibodies are involved?
Blood group A:
- A antigen
- anti-B abody
Blood group B:
- B antigen
- Anti-A abody
Blood group AB:
- A antigen AND B antigen
- no abodies
Blood group O
- no antigens
- both anti-A and anti-B antibodies
IgM antibodies - naturally occurring
Describe the inheritance of ABO blood group
A and B genes are on chromosome 9, A and B are co-dominant and are both dominant over O
Genotype - phenotype: AA - Group A AO - Group A BB - Group B BO - Group B AB - Group AB OO - Group O
Rhesus D:
What is this referring to?
Describe the inheritance
If Rh(D) negative, when would anti-Rh(D) antibodies be made?
Rh(D) is another protein that may or may not be present on RBC’s.
To be Rh(D)-ve have to have autosomal recessive inheritance, gene is on chromosome 1.
Rh(D) -ve person only makes antibodies when exposed to Rh(D) antigen and this is only possibly on exposure to blood (transfusion or pregnancy)
If a Rh(D) negative person recieves Rh(D) positive bloood transfusion what will happen?
On first exposure, 80% of people will have a delayed haemolytic reaction and produce anti-D abodies. Thereafter, Rh(D) positive blood will produce a brisk haemolytic reaction
What lab test is used to determine ABO and Rh(D) grouping?
Antigen-Antibody reaction
For ABO grouping:
-The blood is taken and anti-A abodies is added to one test tube, anti-B antibodies is added to another
-if the blood contains antigen = agglutination
For Rh(D): -monoclonal anti-D abody is added and if this = agglutination Rh(D) +ve.
(if blood group B: contain B antigen so when anti-B abodies are added = agglutination)
What are irregular antibodies? how are these tested for?
These are other RBC markers which the body creates IgG antibody to (anti-kell, anti-duffy, anti-kidd)
- patient only develops these after previous RBC exposure
- patient usually DOESN’T form antibodies to these antigens however these are still checked just in the rare case that they do.
-these are checked for with indirect coomb’s test
What is the indirect coombs test?
- Recipient serum is added to the donor blood sample
- anti-human igG is added (coombs reagent)
- if recipient has igG abodies to the donor blood, when coombs reagent is added = agglutination
(the only difference between indirect and direct coombs is that in indirect the serum has to be added for the antibodies to associate with the RBC’s, in direct coombs the antibodies are already assoc. and coombs reagent is just added straight away)
What happens in group and save? how is this different from a crossmatch?
- Patients with <30% chance of needing RBCs
- test ABO, Rh(D) and irreg. antibodies
- if irreg. antibody screen is negative: go no further and keep patient sample and save info.
- if irreg. antibody screen positive, identify abodies and crossmatch and set aside compatable units.
In a crossmatch a group and save is done and then blood is set aside for the patient
What are two indications for blood transfusion?
-Acute blood loss
Aneamia with:
- reduced exercise capacity
- coincidental -medical/surgical problems
- heart or lung disease
- “anaemic” symptoms
Others: sickle cell/thalassaemia
When transfusing platelets does a crossmatch need to be done? when is this needed?
no but account taken of ABO and Rh(D)
-low platelets
In what 4 scenarios is a transfusion of fresh frozen plasma needed?
Coagulopathy:
- DIC
- coagulopathy following massive transfusion
- bleeding/surgery in liver disease with impaired coagulation
- oral anticoagulant overdose
In an immediate transfusion reaction:
- what usually causes this?
- which 3 systems are activated?
Usually caused by ABO incompatability, IgM abodies bind to the transfused RBCs and:
- activate complement cascade immediately = membrane attack complex
- materials released from the haemolysed RBCs activate coagulation systems: can lead to DIC
- activated factor 7 activates the kinin system = bradykinin formation = arteriolar dilatation and increased vascular permeability = hypotension and release of catecholamines which leads to vasoconstriction within kidneys
What clinical complications does the activation of the three systems in an immediate transfusion reaction have on the body?
systemic hypotension DIC renal vasoconstriction formation of renal intravascular thrombi shock renal failure - OFTEN FATAL
what are the acute clinical features of an immediate haemolytic transfusion reaction?
may begin after only 1 ml is transfused pyrexia / rigors faintness / dizziness tachycardia / tachypnoea / hypotension pallor / sweating headaches / chest or lumbar pain local pain at infusion site cyanosis patient may say “something is wrong” all of this may be difficult to recognise if patient is unconscious
What is the management of an immediate haemolytic transfusion reaction?
- stop transfusion
- start IV fluids: maintain BP and urine output
Take bloods and send with remains of unit:
- FBC and film
- U+E
- Lactate
- Coag. screen
- Blood culture
- Serum haptoglobin
Delayed haemolytic transfusion reaction:
- which type of antibodies are usually implicated?
- presentation
-Irregular IgG antibodies
Presentation:
-variable
- symptoms / signs similar to, but less acute than,
a IHTR
-unexplained fall in Hb value as transfused red cells
are destroyed
-appearance of jaundice, renal failure or biochemical features associated with IHTRs
-detection of positive DAGT or irregular antibodies
in post- transfusion blood samples
What is the pathophysiology of a delayed haemolytic transfusion reaction?
Ab-Ag reaction doesn’t activate complement but coats RBCs which go through the spleen and are attacked by macrophages = spherocytes
What test can be done to check for antibodies in a delayed haemolytic transfusion reaction?
direct coombs
positive DAGT and/or appearance of red cell allo-antibody
In a delayed haemolytic transfusion reaction:
- blood film
- which biochemical markers are elevated
- which organ may have a degree of failure?
anaemia, spherocytic red cells on blood film
elevated bilirubin and LDH
+/- a degree of renal failure
What is a febrile non-haemolytic transfusion reaction? when does this happen?
- occur either because recipient has anti-HLA antibodies that bind to residual white cells within transfusion, or as a result of vasoactive and pyrogenic substances being released from white blood cells during storage of blood components.
- 2% RBC trans., 20% platelet transfusion
What are the clinical features of febrile non-haemolytic transfusion reaction?
rapid temp. rise
chills
rigors
