Blood Transfusion Flashcards
What are the two main grouping systems in blood products?
ABO grouping system
Rhesus grouping system
What two main grouping systems need to be known to minimise transfusion reactions?
ABO grouping system
* antigens attached to RBC cell surface.
Rhesus grouping system
* rhesus D = most immunogenic, so most likely to precipitate a transfusion reaction.
Describe the ABO Grouping system
1. how are antigens inherited?
2. what antigens and antibodies does each group have?
3. why is understanding the ABO grouping system important?
- one ABO allele from each parent - A and B alleles are co-dominant
- Group A have antigen A and antiB antibodies. Group B have antigen B and antiA antibodies. Group AB have both antigen A and B. and neither antibody. Group O have neither antigen, but have both antiA and antiB antibodies.
- Important - have ABO antibodies in plasma.
* these recognise and attack RBCs that express foreign antigens
* antibodies develop in first few years of life
* important in blood transfusion
* if give incompatible blood group to someone = fatal
What type of immunoglobulins are A and B antibodies?
IgM
What blood group is a universal acceptor of blood?
Why are they an acceptor?
AB+ve
* can have any donor blood - so A, B, AB, O, Rh+ve or Rh-ve.
* an acceptor as they have no A or B antibodies in plasma and no Rhesus anitbodies.
* because of this - the body can not initiate an immune response to donor blood.
What are the Rh D groups?
list and describe them
RhD +ve –> have the Rh D antigen and can recieve both Rh+ and RH- blood
RhD -ve –> lack the Rh D antigen and should only recieve Rh- blood
Why should Rh- patients only receive Rh- blood?
- Anti-D antibody is usually absent in Rh- patients (until they have been exposed to Rh+ erythrocytes).
- Rh- patients should not be transfused with Rh+ blood as this can cause them to develop anti-D antibodies.
- This may cause transfusion reactions in the future.
What blood type are universal donors, and why?
- People with blood type O- are universal donors
- they can donate their blood to anyone.
- This is because their RBCs have no A, B, or RhD antigens which the recipient’s immune system could attack.
Describe haemolytic disease of the newborn (HDN)
1st pregnancy
* Mother is RhD-ve. Her partner is RhD+ve.
* She becomes preggo with fetus who is RhD+ve.
* In childbirth, mother comes into contact with the foetal RhD+ve blood
* Because of this, she makes has RhD sensitisation and makes antibodies to the RhD+ve. She has produced anti-D antibodies which are in her maternal circulation. This is a first exposure - antibodies are IgM so can NOT cross the placenta.
* If the mother becomes pregnant again with a child who is RhD+ve = not good.
2nd pregnancy with child who is RhD+ve
* Mothers anti-D antibodies can cross the placenta during this pregnancy –> foetal circulation containing RhD+ve antigens.
* Maternal anti-D antibodies recognise and destroy foetal Rh+ RBCs.
* Why? This is a second exposure –> anti-D antibodies are IgG which can cross the placenta and cause haemolysis.
* leads to foetal anaemia = HDN.
What happens when you give a RhD-ve patient RhD+ve blood transfusion?
When would this specifically be a problem?
- the patient will make RhD antibodies
- for the patient - this is not a problem as their blood does not have RhD in - so have nothing to attack
This would be a problem during pregnancy
* anti-D antibodies (made from the intiial blood recieved) can cross the placenta
* cause haemolytic disease of the newborn
* so need to give women blood specific to their RhD status.
What investigations/tests do you need to do before giving a patient blood transfusion?
- Group and save
- Cross match
What is a group and save blood test?
- aka ABO typing
- tests the patient’s blood for the presence of A/B antigens, A/B antibodies and Rh typing.
- The lab will also screen the patient’s blood for atypical antibodies
- takes ~40mins
- blood can NOT be issued after this test alone.
What is cross-matching?
- involves mixing the donor’s blood with the recipient’s blood to detect any immune reaction.
- takes ~40mins to do this after an initial 40mins to G+S
- if no immune reaction = donor blood CAN be issued and transfused into patient.
In blood transfusion…
What is electronic issue (EI)?
Leeds Teaching Hospital website:
* Electronic Issue is the process whereby blood is issued to a patient without crossmatching thus creating a large time saving for urgent and theatre cases. For EI to be applied, certain strict criteria must be met.
NHS website:
- Electronic issue (EI) is the selection and issue of red cell units where compatibility is determined by the Laboratory Information Management System (LIMS) without serological testing (serological crossmatch) of donor cells against patient plasma.
What is the Coombs’ test?
Describe direct and indirect Coombs’ test
Detects presence of antibodies against RBCs.
Direct:
* mix patient blood with coombs’ reagent
* coombs’ reagent binds to specific immunoglobulins on RBCs
* positive result = RBCs clump together (agglutinate)
Indirect:
* used in cross matching and to detect anti-D igG.
* Donor’s RBCs and Coombs’ reagent is combined with the patient’s isolated plasma
* positive result = if agglutination occurs. i.e. patient has antibodies against the antigens in donor’s RBCs.
Explain how to take and label blood samples and request blood components for transfusion
Check patient details
* Using 3 points of identification to check you are with the correct patient (name, DOB and patient number).
Consent
* Consent the patient appropriately – many transfusion request forms will now have a script on them, which you should read to the patient. A consent form (as you would use for consent for any procedure) is completed.
Labelling
* Labelling the bottle at the bedside (pre-printed stickers for blood transfusion are usually not allowed in many countries, including the UK)
Request transfusion
* Completing the transfusion request form at the bedside. Before you put the blood bottle into the request bag, check with the patient that they are happy you have labelled things correctly.
What is Hb concentration threshold for patients needing blood cell transfusion?
Current NICE guidelines recommend a restrictive haemoglobin concentration threshold of 70 g/L for those who need red blood cell transfusions (without any major haemorrhage or acute coronary syndrome) and a haemoglobin concentration target of 70-90 g/L after transfusion
How is blood safely stored?
- RBC are stored between 2-6 degrees and can be kept for up to 35 days
- Platelets are kept at 22 degrees and are only kept for 5 days. Note: Moving shelves which stop them sticking together
- Plasma and cryo are frozen and stored in freezers for up to one year
from Sas
How are blood products safely administered?
* what needs to be done to blood before administration?
* how should they be prescribed if more than one unit is needed?
* what observations are required?
* what cannula is used? and why?
Blood must be warmed to prevent hypothermia and prevent haemolysis.
If a patient requires more than one unit of blood, each unit must be prescribed individually.
Whilst the patient is receiving the transfusion, there are specific observations timings that should be carried out:
- Before the transfusion starts.
- 15-20 minutes after it has started.
- At 1 hour.
- At completion.
Blood products should only be administered through a 18G or 16G cannula, otherwise the cells haemolyse due to sheering forces in the narrow tube.
NICE guidelines suggest single unit red blood cell transfusions for the surgical patient who does not have active bleeding, reassessing the patient after each transfusion.
What are blood donors screened for?
- Syphillis
- Hep B
- HIV
- HepC
- HepE
- Human T-lymphotropic virus
- Malaria
- T-cruzi - Trypanosoma cruzi
- West Nile Virus
- Cutomegalovirus (CMV)
How are blood donors recruited?
Volunteers
This Is Amazing - NHS Blood donation campagn = celebrate donors and urge others to join/volunteer.
What are the different types of blood products that can be transfused?
Red cell transfusion
Platelet transfusion
Cryoprecipitate
Fresh frozen plasma
Prothrombin complex concentrate
Note: when a donor gives blood, it is separated into these different parts.
What are the indications for red cell transfusion? (aka packed red cells = red blood cells)
Indications
* Acute blood loss
* Chronic anaemia, where the Hb ≤ 70g/L (or ≤ 80g/L in those with cardiovascular disease) or symptomatic anaemia
For packed red cells (red cell transfusion), what duration is it administered over?
2-4 hours. It must be completed within 4 hours of coming out of the store
After giving 1 unit of blood, how much will patient’s Hb increase by?
10 g/L
Why would a patient given red blood cells need a new G+S to be done?
- Patients given red blood cells may produce autoantibodies to donor surface antigens (of which there are many, other than ABO and RhD).
- Because of this, before any future transfusions, a new G&S will need to be sent (unless the last G&S was sent and processed within around 3 days of the most recent transfusion).
What are the indications for platelet transfusion?
- Haemorrhagic shock in a trauma patient
- Profound thrombocytopenia (< 20 x 10^9/L; normal range 150 – 400)
- Bleeding with thrombocytopenia
- Pre-operative platelet level < 50 x 10^9/L
What duration is a platelets transfusion administered over?
30 minutes
After giving 1 adult theraputic dose of platelets, how much should platelet levels increase by?
20-40 x 10^9 /L
- What are irradiated blood products?
- Why are they required?
- What groups of people should recieve them?
- Blood that is treated with low dose radiation to stop lymphocytes(WBC) in donated blood from harming patients with weak immune system
- required to reduce the risk of transfusion associated graft-versus-host-disease in at risk populations. This occurs when the donor WBCs attack the patients tissues
- Groups:
* Those receiving blood from first or second-degree family members
* Patients with Hodgkin’s Lymphoma
* Recent haematpoietic stem cell(HSC) transplants
* After Anti-Thymocyte Globulin (ATG) or Alemtuzumab therapy
* Those receiving purine analogues (e.g. fludarabine) as chemotherapy
* Intra-uterine transfusions
* SCID
What is the management for massive blood loss?
see pic
Summarise blood products you would give in a code red major haemorrhage
Thought was a good summary of deck so far
Describe cell salvage
an alternative to blood transfusion
Intraoperative = collect blood that is lost and give it back to patients
Autologous blood transfusion = blood colecting using suction, anticoagulant is added to stop it clotting. RBC are washed, filtered and returned via cannula after operation.
How does TRALI present?
Develop within 6hours of transfusion
* sudden onset dyspnoea
* severe hypoxaemia.
* fevere
* hypotension
* CXR shows pulmonary infiltrates
What is main difference between TACO and TRALI?
TRALI = pt is hypotensive, also have a fever
TACO = pt is hypertensive
Before each unit of blood, you should?
(5 things - on a blood transfusion bedside checklist)
Note - for 3 on right side of pic= ask for 3 points of ID - name, DOB, S number
The transfusion of packed red cells has been shown to increase serum levels of what electrolyte?
passmed
Potassium - when you transfuse packed red cells, it can increase potassium levels = causing hyperkalaemia. The risk is higher with large volume transfusions and with old blood.
A pt with an ECG will have associated changes.
AR possible blood transfusion reactions
Mnemonic = Got a bad unit
Compare and contrast TACO and TRALI
from blood transfusion slides
