Blood Transfusion Flashcards
What is donated blood screened for?
Hep B, C, E
HIV
HTLV
Syphilis
How are red cells stored?
At 4 degrees Celsius for 35 days
How is FFP stored?
-30 degrees for 3 years
How are platelets stored?
At 22 degrees with agitation for 7 days
Name three blood products
Anti-D
Prothrombin
IV Igs
Human albumin
What are antigens made of?
Sugar and protein
Where is the ABO gene expressed?
Chromosome 9
What is substance H?
A transferase which is modified into A or B
Which ABO antibodies are present with blood group A?
anti-B
Which ABO antibodies are present with blood group B?
anti-A
Which ABO antibodies are present with blood group O?
anti-A
anti-B
Which blood groups can blood group A receive?
A and O
Which blood groups can group B receive?
B and O
Which blood groups can AB receive?
A, B, AB and O
Which ABO antibodies are present in blood group AB?
None
Which blood groups can O blood group receive?
O
What is Landsteiner’s law?
If there is no A or B antigen expressed, antibodies will be made to A or B in the plasma
What are anti-A and anti-B antibodies made in O blood groups?
Bacteria with a similar structure to A and B are present in the gut bacteria, so antibodies are made against these
What is used to determine ABO blood group?
Anti-A and anti-B antisera
How are D, K Jka and Fva antibodies tested for in blood?
Indirect anti-globulin test
Why is anti-human globulin added to suspension in the indirect anti-globulin test?
IgG is used but as this only has two binding sites agglutination is not clear
Anti-human globulin binds to the IgG when bound to red cels to enhance the agglutination
What are the indications for red cell transfusion?
Symptomatic anaemia Hb <70 (<80 in heart disease)
OR
Major bleed
What are the indications for platelet infusion?
Prophylactically in marrow failure and very low platelet count or prior to surgery in thrombocytopenia
OR
In bleeding thrombocytopenic patient
What are the indications for FFP transfusion?
Bleeding in coagulopathy with PT >1:5
Major haemorrhage
Early trauma
Prophylactically in coagulopathy before procedure
What is the first thing to do in management of blood transfusion?
Stop the transfusion
Why does fever occur in acute transfusion reactions?
Cytokine release
How do acute transfusion reactions occur?
Chills, rigors, fever Flushing Collapse Loin pain Resp distress Tachycardia Hypotension
When should senior help be requested with transfusion reactions?
Airway/breathing problems
Shock
Evidence of bacterial infection
What checks should be performed in transfusion reaction?
Compatibility tag should be checked against patient details
Inspect pack for evidence of bacterial contamination
Which antibody causes acute haemolytic transfusion reactions?
IgM
What does IgM cause in acute haemolytic transfusion reactions?
Complement activation
Lysis of transfused cells and cytokine release
What tests should be performed in acute haemolytic transfusion reactions?
Coag screen
Blood cultures
Renal function
What life-threatening conditions does acute haemolytic transfusion reaction lead to?
DIC
Renal failure
How does TACO present?
Resp distress within 6 hours Increased BP and JVP Positive fluid balance Oedema Bibasal crackles
What risk factors are associated with TACO?
Elderly Cardiac failure Low albumin Renal impairment Pre-existing fluid overload
How is TACO managed?
O2 and diuretics
Slow rate of future transfusions and give min volume req’d
What are the criteria for a mild transfusion reaction?
Isolated temp rise >38 degrees and a rise of at least 1 degree
OR
rash only
How are mild transfusion reactions managed?
Slow rate of transfusion
Paracetamol and anti-histamine
What antibody is involved in delayed haemolytic transfusion reaction?
IgG
When does delayed haemolytic transfusion reaction occur?
5-10 days post transfusion
What investigation results confirm delayed haemolytic transfusion reaction?
Positive DAT scan
Alloantibody detection
What type of reaction is an ABO incompatibility reaction?
Type II hypersensitivity
Which antibody is involved in ABO incompatibility reactions?
IgM
What does Hb appear in urine in ABO incompatibility reactions?
Membrane attack causes cell lysis and free Hb is excreted through the urine
What occurs in transfusion associated lung injury?
Antibodies in donor blood directed against patients white cells
What is the risk of viral transmission of Hep B through transfusion?
< 1 : 1.2mil
What is the risk of viral transmission of HIV through transfusion?
<1: 7 mil
What is the risk of Hep C transfusion through transfusion?
< 1: 28mil
