Blood transfusion Flashcards
1
Q
What are the minimum criteria for blood donation?
A
- Hb 135g/L Men
- Hb 125g/L Female
- Weight >50kg
2
Q
What microbiological testing is required for blood donations?
A
HIV, Hep B, Hep C, Hep E, HTLV and syphilis
3
Q
In what conditions are red cells stored?
A
4ºC for 35 days
4
Q
In what conditions is fresh frozen plasma stored?
A
-30ºC for 3 years
5
Q
In what conditions are platelets stored?
A
22ºC for 7 days with agitation (Shaking)
6
Q
What blood components are available from the transfusion lab?
A
Red cells
Fresh frozen plasma
Platelets
Cryoprecipitate
7
Q
Why does stored blood have a reduced ability for metabolising tissue?
A
It has less 2,3-DPG, so has a higher affinity for oxygen
8
Q
How many donations are required for 1bag of platelets?
A
4 separate donation or 1 porphoresis donations (Specific platelet donation)
9
Q
What blood products (Not components) are available from the transfusion lab?
A
- Anti-D immunoglobulin
- Prothrombin complex concentrate (Warfarin reversal)
10
Q
What pharmaceutical blood products are available from the pharmacy?
A
- IV immunoglobulin
- Human albumin
- Specific immunoglobulins
11
Q
What are the main 2 blood grouping techniques?
A
ABO grouping
Rhesus grouping
12
Q
What chromosome determines ABO group?
A
Chromosome 9
13
Q
What is the normal function of A and B genes?
A
They code for transferases, which modify a precursor called “H substance” on red cell membranes
14
Q
What genes may be present in an O type person?
A
OO genes only
15
Q
What genes may be present in an A type person?
A
AA
AO
16
Q
What genes may be present in a B type person?
A
BB
BO
17
Q
What genes may be present in an AB person?
A
AB
18
Q
What is Landsteiner’s law?
A
Landsteiner’s law states that when an individual lacks A or B antigens, the corresponding antibody is produced in their plasma (Won’t produce antibodies against those that you have)
This is why there is selectivity in transfusion
19
Q
What are the 4 main ABO blood types?
A
O - 47% population - No antigens
A - 42% population - A antigens
B - 8% population - B antigens
AB - 3% population - AB antigens
20
Q
Which blood group is the universal donor?
A
Group O (Rh -ve)
21
Q
Which blood group is the universal receiver?
A
Group AB (Rh +ve)
22
Q
What is tested for in Rh grouping?
A
Blood is typed for the presence or absence of a rhesus protein (RhD)
23
Q
What percentage of the population is RhD positive?
A
85%
24
Q
What genes are present in RhD positive people?
A
DD
Dd
25
What genes are present in RhD negative people?
dd
26
What is involved in pre-transfusion testing?
Pre-transfusion testing involves a grouping screen to identify ABO and RhD grouping, using a forward test and then a reverse test (To check)
Indirect anti-globulin testing for antibody screening
27
What is involved in forward blood group testing?
The forward test involves antisera, which are reagents with known antibody specificity to identify antigens present on the red cells (Anti-A, Anti-B and Anti-RhD)
28
What is involved in reverse blood group testing?
The reverse test involves reagent red cells, which use red cells with known antigen specificity to identify antibodes present in plasma (Landsteiner’s law)
29
What will show a positive result in blood group testing?
Agglutination of red blood cells
30
What is involved in indirect anti-globulin testing?
Anti-human globulin is added to the suspension, which facilitates red cell agglutination
This is to ensure there is compatibility based on other anti-RBC antibodies
This is usually performed using around 10 different antibodies
31
What information does a patient required to give valid consent for transfusion?
BRAN:
- Benefits
- Risk
- Alternatives
- Nothing (Effects of doing nothing)
32
Why can't patients donate blood after receiving a transfusion?
To avoid risk of CJD
33
What happens if a patient cannot consent at the time (e.g. car crash)
It is ensured that they are informed afterwards and the transfusion is documented in the discharge letter to the doctor
34
What are some indications for red cell transfusions?
- Symptomatic anaemia (Hb<70g/L)
- Major bleeding
35
What are some indications for platelet transfusion?
- Prophylaxis in patients with bone marrow failure and very low platelet counts
- Treatment of bleeding in thrombocytopenic patients
- Prophylaxis prior to surgery in thrombocytopenic patients
36
What are some indications for fresh frozen plasma transfusions?
- Treatment of bleeding in patient with coagulopathy
- Prophylaxis prior to surgery or procedure in patient with coagulopathy
- Management of massive haemorrhage
- Transfuse early in trauma
37
What are the 10 stages of the transfusion process?
1. Consent
2. Request
3. Sample taking
4. Sample request reciept
5. Testing
6. Component selection
7. Component labelling
8. Component collection
9. Prescription
10. Administration and monitoring
38
When are observations and monitoring performed in the transfusion process?
- Observation before commensal
- Observation at 15 minutes
- Observation within 60 minutes of completion
39
What is haemovigilance?
Haemovigilance is the voluntary reporting of adverse events and near misses relating to transfusion to SHOT (Serious Hazards Of Transfusions), who then publish annual recommendations for improving transfusion safety
40
What are the 2 main types of transfusion reaction?
- Acute transfusion reactions (ATR)
- Delayed transfusion reactions
41
What are some symptoms of acute transfusion reactions?
- Chills
- Rigors
- Rash
- Flushing
- Agor amini
- Collapse
- Loin pain
- Respiratory distress
42
What are acute transfusion reactions?
Acute transfusion reactions are those that occur early on in transfusion
43
What are some clinical signs of acute transfusion reaction?
Fever
Tachycardia
Hypotension
44
What are the 3 classes of acute transfusion reaction?
Mild
Moderate
Severe
45
What are the first steps in managing a suspected acute transfusion reaction?
Stop transfusion
ABCDE assessment
Re-check compatibility
Inspect for contamination evidence
Document the event
46
How are mild acute transfusion reactions classified?
Mild acute transfusion reactions are classified by an isolated temperature rise >38 of 1-2ºC (<39ºC) or a rash only
47
How are mild acute transfusion reactions managed?
Management involves restarting the transfusion, possibly at a slower rate, close monitoring of the patient and possible paracetamol and anti-histamine
48
What are the 2 most probable causes of mild transfusion reaction?
- Febrile non-haemolytic transfusion reaction
- Mild allergic reaction
49
What causes febrile non-haemolytic transfusion reactions?
This is caused by a possible small number of donor white cells in the transfusion which attack the patient and cause a slight fever or rash
50
What causes mild allergic reaction in transfusion?
Non-self proteins on platelets or in the plasma
51
How are moderate acute transfusion reactions classified?
Everything that is not mild or severe is classified as moderate
This include significant temperature rises, respiratory complications and allergic reactions
52
What are some possible respiratory complications of moderate transfusion reactions?
- Transfusion associated circulatory overload (TACO)
- Transfusion related acute lung injury (TRALI)
53
What is transfusion associated circulatory overload (TACO)?
This is a condition in which increased blood volume due to the transfusion results in pulmonary oedema
54
How will TACO present?
- Respiratory distress within 6 hours of transfusion
- Raised blood pressure
- Raised JVP
- Positive fluid balance
55
Who is most at risk of TACO?
This is most common in patients with an already increased blood volume, due to conditions such as age, cardiac failure, low albumin, renal impairment and fluid overload
56
How is TACO managed?
Management involves oxygen, supportive care and diuretics
57
What will happen in required future transfusions in a patient with previous TACO?
If future transfusions are required, the rate may be slowed and diuretics may be given prophylactically
58
How are severe or life-threatening transfusion reactions classified?
- Life-threatening airway problem
- Life-threatening breathing problem
- Life-threatening circulatory problem
- Wrong component transfused
- Bacterial contamination
59
What is the immediate management strategy in severe transfusion reaction?
The immediate management would be to seek senior medical assistance, resuscitate the patient, discontinue transfusion and return the components to the transfusion lab to allow for further investigation
60
What are the 3 main causes of severe transfusion reactions?
- Acute haemolytic transfusion reaction
- Bacterial contamination of the blood
- Anaphylaxis
61
In which blood product is bacterial contamination most likely?
Platelet transfusions
62
How is bacterial blood contamination managed?
In cases of suspected bacterial contamination, cultures of the patients blood and the remaining donor blood must be taken
Supportive treatment with broad spectrum antibiotics is required
It is also important to inform the transfusion lab, so that other units can be quarantined
63
How do acute haemolytic transfusion reactions (AHTR) occur?
This occurs when ABO or Rh incompatible blood is given to a patient (ABO is the most dangerous)
The patients antibodies will haemolyse the transfused cells via release of IgM and inflammatory cytokine release
IgM release against anti-A or B will lead to complement activation and lysis of transfused cells
Inflammatory cytokines will activate the coplement system, kinin system and coagulation system
64
What are some possible complications of acute haemolytic transfusion reaction?
- Shock
- Increased vascular permeability
- Disseminated intravascular coagulation (DIC)
- Renal failure
- Often death
65
How are acute haemolytic transfusion reactions managed?
Management involves stopping the transfusion and returning it to the transfusion lab
Then, start supportive measures such as oxygen and fluids
Repeat transfusion blood samples and take blood for FBC, coagulation screen, renal failure, measures of haemolysis and blood culturing
The transfusion lab will repeat ABO and RhD grouping, direct antiglobulin tests and crossmatching, before sending the remaining units off for culturing
66
What are delayed haemolytic transfusion reactions?
These are reactions in which the patient mounts a delayed immune response to red cell antigens, usually with IgG
This will often result in extravascular haemolysis 5-10 days post-transfusion, causing destruction of transfused cells
This causes a drop in Hb, raised bilirubin and LDH
67
How are delayed haemolytic transfusion reactions tested for?
They will show a positive DAT (Direct Antibody Test)
