Blood Transfusion Flashcards
What are blood components which can be transfused?
Whole blood (we don’t use this is Scotland but could be useful in trauma settings)
Red Cells
Platelets
Fresh Frozen plasma
Cryoprecipitate
What plasma derivatives can be transfused?
Albumin
Immunoglobulin
Coagulation factors
Blood donors - who can donate?
Voluntary people between 17 - 65. The donor needs to be healthy, normal blood levels, weight and how often they donate.
What are blood donors asked when donating blood for blood safety?
Travel, lifestyle, health
Blood safety - what screens do they use on donations?
HIV, hepatitis B, C, E, HTLV, syphilis and others as required
Do you have to tell the blood clinical if you fall ill a few days after donating blood?
Yes
What are all blood donations tested specifically for in order to go in the correct patient?
Blood group and antibodies
What is the process of blood donations?
400 - 500ml of whole blood gets filtered and then split into the different components e.g. platelets, plasma ect.
What are the different ways to get platelets?
Pooled platelets - 4 different platelets are pulled together
Plateletpheresis - platelets are seperatated from the blood during donation and the rest of the blood is put back in the donor.
Red cells as a transfusion - are these in solution and do they need to be in the fridge?
Yes and must be used within 4 hours after removal
Why would you give someone red cells?
To increase the red cell mass to improve oxygen delivery in patients with low haemoglobin levels
What must red cell components be compatable with?
The ABO blood group of the recipient
What is fatal in blood cell transfusion?
ABO-incompatible red cell transfusion
How much haemoglobin is raised in each transfusion?
1g/dl or 10 grams per litre
What temperature are platelets kept at for an how long?
Room temperature for 5 days unless they run bacterial screens and then it can be longer.
Why would you give someone platelets?
If someone has too low plasma or a disorder which causes their plasma not to work correctly.
Does fresh frozen plasma need to be frozen and how long do you have to use it once removed?
Yes and can be kept for 3 years at this temperature - it then needs to be defrosted before being given to someone. You have 4 hours
Why would you give someone fresh frozen plasma?
You need to give it people who have issues with coagulation factors and they are bleeding.
What is Cryopreciptate?
Thaw plasma and get a precipitate of high concentrated fibrinogen
Who would get cryopreciptate?
People who have low fibrinogen
When would you use Granulocytes
These are essentially neutrophils and are used to replace this.
What are the different blood groups?
There are hundreds of blood group antigens with ABO and Rhesus being the most important
What are the ABO blood groups?
A, B, AB, O
What are the antigens found on the group A blood group?
A
What are the antibodies in the group A blood plasma?
Anti-B
What are the antigens found on group B blood cells?
B antigens
What are the antigens found on group AB blood?
AB antigens
What are the antigens found on group O red blood cells?
None
What are the antibodies found in the plasma of group B?
Anti-A antibodies
What are the antibodies found in the plasma of group AB RBC?
None
What are the antibodies found in the plasma of group O RBC?
Anti-A and Anti-B
What immunoglobin class are anti-A and anti-B apart of?
IgM
Are the antibodies to ABO antigens naturally occuring?
Yes
What immunoglobin class are all other antibodies such as Rh apart of?
IgG
What blood group is the universal recipient group?
Type AB as you have no antibodies against A or B.
What blood group are universal donors?
O
If you are in the blood group A what blood types can be transfused into you?
A and O
What is a consequence of ABO-incompatibility?
Acute travascular haemolysis
What does acute intravascular haemolysis do to the body?
complement mediated destruction of the transfused red cells and release of cytokines making a cytokine storms and shock, DIC etc.
How many Rhesus blood group antigens is there?
5 - C/c, D, E/e
What diseases do the IgG anti-D antibodies cause?
Acute of delayed haemolytic transfusion reactions or haemolytic disease of the foetus and newborn (HDFN).
HDFN - what is this?
An incompatability between the blood type of mother and the baby particulary in rhesus D and c.
How does HDNF occur?
This occurs is mum is rhesus D negative and baby is rhesus D positive. If there is blood mixing the mums immune system sees the RhD+ as being foreign and will create allo-antibodies and attack those blood cells.
What are allo-antibodies?
Antibodies produced when an individual is exposed to blood of a different blood group either through transfusion or pregnancy.
What pregnancy does HDNF become and issue in and why?
Any after the first e.g. second baby - as the antibodies have not yet matured during the first. This gets worse with each Rh+ pregnancy.
Treatments of HDFN?
Giving the mum anti-D throughout the pregnancy, if there might be blood mixing (e.g. a trauma) and during birth.
Do you need a sensitising event to make allo-antibodies?
Yes
What are the compatibility procedures for blood transfusion? (5 steps)
A blood sample is given to the lab and they group the blood (ABO and Rh type) and screen for allo-antibodies.
If there is antibodies they want to know what antibodies these are.
Select blood which matches blood type and most closely matches the allo-antibodies.
Crossmatch - This includes a serological blood match by mixing the blood sample from patient with the red cell donation to see if it is rejected (IAT needs to be negative). You could also use electronic issue if certain criteria met (you dont need to mix the blood together)
Label and issue
What happens during emergencies?
The patient is given O RH D negative immediately whilst a blood sample is taken.
It will then take 10 minutes for the ABO, Rh compatable test to be done.
After 30 - 40 minutes you can get fully cross matched blood.
How do you work out if there is any antibodies in the blood?
Antiglobulin tests (Coombs test) using antibodies to IgG, IgM or complement components
What are blood group antibodies specifically identified by?
Indirect antiglobulin test (IAT)
What test specifically idenitfies antibodies present on circulating red cells after a mismatch blood transfusion?
Direct antiglobulin test (DAT)
How is the direct antiglobulin test done?
Blood is taken from the patient and this detects if there is a coating of autoimmunoglobulin on it. Add antihuman globulin which binds everything together giving you a positive result
How does the indirect antiglobulin test work and what are expected results?
Take plasma from the patient and add reagent red cells with relevant antigen (these are IgG and results in no clumping together). You then need to add the antihumanglobulin to make them stick together. You will then get a positive test meaning that you do have some antibodies you need to identify.
Non-infections complications of transfusion - are these acute?
Both acute and delayed
What are some non-infectious acute complications of transfusions?
- Allergies (particularly to plasma)
- Acute Haemolytic transfusion reaction
- Bacterial contamination - sepsis
- Transfusion associated circulatory overload (TACO) - when you give too much fluid e.g blood too quickly and is the most common cause of death in transfusions.
- Transfusion associated lung injury
What are some delayed non-infectious complications of transfusion?
- Delayed haemolytic transfusion reactions
- Transfusion associated graft versus host disease (rare but universally fatal).
- Post transfusion purpura (rare)
Long term Iron overload
What are some infectious complications of transfusion - where do these come from?
Are rare but can come from bacteria, viruses, parasites and prions
What are some rare infectious diseases due to transfusion?
HIV, Hep B etc.
How does the government monitor haemolytic transfusion?
Serious hazard of transfusion (SHOT) - this is voluntary reporting of adverse effects.
MHRA - this is a legal requirement reporting of adverse events and reactions.
What are some alternatives to transfusion?
Patient blood management programmes
- Maximuse haemoglobin before surgeon e.g. iron replacement
- ESA - erythropoietin stimunlating agents
- Stopping anticoagulants’antiplatelets agents before surgery
- Intra-operative cell salvage (all the blood removed from patient during surgery is filtered and put back into patient)
- Anti-fibrinolytic drugs
