Blood Transfusion Flashcards
Reasons to transfer blood
Bleeding (Mainly)
Failure of production
Features of antigens of blood groups
Red cell antigens expressed on cell surface (proteins, sugars, lipids)
Can provoke antibodies
What is an antigen?
Something that provokes an immune response
Blood group types
Type A
Type B
Type AB
Type O
Antigens of the ABO blood groups
ABO - glycosyltransferase A and B - transferase enzymes A = N-acetyle-galactosamine B - galactose 0 - non functional allele SO A AND B ARE CO DOMNANT AND O IS RECESSIVE
Most common blood types
A and O
Rarest blood type
AB
If you have blood group A, what do you have antibodies against?
B
If you have blood group B, what antibodies do you have against?
A
If you have blood group O, you have antibodies against……
A and B
if you have blood group AB, you have NO antibodies against….
A and B
What blood group is a universal donor?
Blood Group O
What blood group is a universal recipient?
Blood group AB
What does FFP contain and not contain compared to blood?
DOES NOT Contain the antigen but contains the antibody
What is RhD?
An antigen which is a transmembrane protein, with ion channels and is hydrophobic
How many RhD proteins do people usually have?
2
Types of RhD blood group system
RhD +ve
RhD -ve
Who can make anti-RhD and why?
RhD negative individuals can make anti-D if exposed to RhD+ cells during
- transfusion
- pregnancy
What can anti-D cause?
Transfusion reactions
haemolytic disease of the newborn
What is tested/looked at in blood donors?
Extensive 'behavioural screening' - sex - age - travel - tattoos Tested for ABO and Rh Blood groups Screened for - Hep B/C/E - HIV - Syphilis Variable screened for (if travelled to certain parts of the world) - HTLV1 - Malaria - west nile virus - zika virus
What do apheresis donors do?
Just take off platelets or just FFP etc
Indications for red cell transfusion
- to correct severe acute anaemia, which might otherwise cause end organ damage
- to improve QoL in patient with otherwise uncorrectable anaemia
- To prepare a patient for surgery or speed up recovery
- to reverse damage caused by a patients own red cells e.g. sickle cell disease
Storage and transfusion of RBCs
Stored at 4C (2 - 6 range)
Transfused over 2-4 hours
Storage and transfusion of platelets
1 dose platelets (=4 pooled or 1 apheresis donor)
stored at approx. 22C
shelf life 7 days
transfuse over 20-30 mins
Indications for platelet transfusion
Massive haemorrhage
Bone marrow failure
Prophylaxis for surgery
Cardiopulmonary bypass (only use if bleeding)
Components of a platelet transfusion
Fresh frozen plasma
Cryoprecipitate
Storing of FFP
Stored frozen, allowed 30 mins to thaw
Indications for FFP transfusion
Massive haemorrhage (1:1 ratio)
DIC with bleeding
Prophylactic
Lab tests for FFP
PT and APTT
Storing of cryoprecipitate
Stored frozen, allowed 20 mins to thaw
Cooling FFP at 4C slowly to form the precipitate
Lab test of cryoprecipitate
Fibrinogen
What does cross match tariff defined by MSBOS mean?
You will have this blood ready ahead of time due to the patient
How long are Samples in a blood bank kept for?
7 days
only valid for 2 days if recent transfusion
When is Coombs test positive?
Clumping together of antihuman immunoglobulin to antibodies due to antibody being bivalent
Causes of Coombs test positive
Direct - autoimmune haemolytic anaemia - passive anti-D - haemolytic transfusion reactions Indirect - cross matching
Blood requirements immediately during a massive haemorrhage
6 units of red cells
4 units FFP (cryoprecipitate?)
1 unit platelets
Risks of blood transfusion
Never events (death/harm due to transfusion of ABO incompatible components)
TACO (too much blood too quickly)
ATR
Fever
What does TACO stand for?
Transfusion associated circulatory overload
What does ATR stand for?
Acute transfusion reaction
What is prion disease caused by?
Abnormal prion protein from mad cow disease
How to catch prion disease
Transmittable by blood transfusion from earl in disease in sheep
mainly found in older people
another reason not to transfuse blood unless really have to
Adverse reactions of a blood transfusion
TACO AHTR Bacterial infection TRALI Pyrexia urticaria dyspnoea Shock
What does AHTR stand for?
Acute haemolytic transfusion reaction
Pathology of haemolytic disease of the newborn
Development of maternal Anti D antibodies (sensitisation)
IgG crosses the placenta
So the mothers RhD negative antibodies go into the placenta and interact with the RH positive blood cells
This causes haemolysis in the foetal circulation
Prevention of haemolytic disease of the newborn
Prophylactic Anti-D
- sensitising events
- routine at 28/34
Treatment of haemolytic disease of the newborn
Careful monitoring - antibody titres - doppler US - IU transfusion Delivery Intrauterine transfusion though cannulation of umbilical vein (if cannot deliver baby as too early) Leucapheresis (bone marrow harvests, donor lymphocyte infusions) Bone, milk, heart valves, faecal banks gene therapies
Pathology of transfusion related acute lung injury (TRALI)
Transfused anti-leucocyte Abs in donor plasma interact with the patients WBCS
Bilateral pulmonary infiltrate
Treatment of TRALI
Supportive
Ventilation
What does PTP stand for?
Post transfusion purpura
When does PTP occur?
RARE 7-10
days after transfusion of blood or platelets
Pathology of PTP
HPA 1 negative patients form antibodies after transfusion or pregnancy
after further transfusion destruction of own platelets
Pathology of transfusion associated graft vs host disease
Rare but always fatal
Graft of lymphocytes in donors blood
- transfused to an immunocompromised host
- homozygosity of donors HLA type
How can transfusion associated graft vs host disease be prevented?
Irradiation of blood
Is any transfusion risk free?
No
What is intraoperative cell salvage?
Gives the patient back their own blood and reduces the risk of needing a transfusion
In what ways can a need for blood transfusion be minimised?
Autologous programmes such as intraoperative cell salvage, intra or post operative may be considered
Pre operative care, anaemia correction with iron, stop aspirin/warfarin where possible etc
EPO (recombinant human erythropoietin) can stimulate red cell production in some circumstances
How long can blood live outside the body for?
35 days
What do neonates < 1 y/o use for blood transfusions?
Peedie pack
What does a peedie pack consist of?
Special donors for neonates where 1 donation is split into 5 30ml individual donations
The other 4 will be reserved for the same neonate if one is used so not getting 5 different donations
What is the biggest risk of blood transfusion?
Error in administration of blood
What is the shelf life for FFP and cryoprecipitate and why is this?
3 years
As stored frozen
What does code red consist of?
Activating major haemorrhage before at the hospital so can have FFP and cryoprecipitate thawed to be ready
Once FFP is thawed, how long is it viable for?
4 hours
What would happen to platelets If they were put into a fridge?
They would die
Who needs irradiation of their blood?
Haematology patients
Some MS patients
Some patients on certain drugs
Why do people need their blood irradiated?
Their immune system is so slow they could not handle the T lymphocytes from the donors blood
What does blood irradiation prevent?
Transfusion associated Graft vs host disease
After a sensitising event / birth of a baby, within what time limit must Anti D be given?
Within 72 hours
How long would a T number sticker stay on an ID band for?
However long the sample is viable so should only ever have one at one time
What must be checked of the blood unit prior to infusion?
No pack leakage Transfusion port in tact No evidence of haemolysis No gas / discolouration / clots Donation number - pack matches label Compatibility label against patient's wristband Blood group - pack compatible with label Expiry date - not passed
Current risks of blood transfusion in the UK
Hepatitis B Hepatitis C HIV/AIDs vCJD Hepatitis E
How much is a unit of blood?
470ml (+/- 50ml)
What does a unit of blood consist of?
270 ml of red cell concentrate
Suspended in plasma plus additive solution
What is the donation tested for?
HIV HBV HCV HTLVI/II Syphilis
In a 70kg recipient, one unit of blood should increase the Hb by how much?
9g/L
How must red cells be stored?
4C
Until < 30 mins before required
How is the blood given?
Each unit given over 2-3 hours
Infusion flow rate of approx. 100mL/hour
Indications for red cell transfusion
Perioperative/ITU transfusion
Bone marrow failure
Rarely used to treat iron and other haematinic deficiencies
What to tell the patient about red cell transfusion
Reason for transfusion Treatment options Valid alternatives Option to refuse Risks of transfusion
Management of serious adverse reactions of red cell transfusions
STOP THE TRANSFUSION
keep all residual blood packs
Recheck identity of patient, blood unit and documentation
Check and record patients BP, pulse, RR, and check for dyspnoea, tachypnoea, wheeze, cyanosis
Notify blood bank
Check blood gases or O2 sats
Maintain airway
Seek advise if condition continues to deteroriate
Adverse events of transfusion
Fluid overload Acute haemolytic transfusion reaction Infusion of a bacterially contaminated unit TRALI Severe allergic reaction or anaphylaxis
Where must serious adverse reactions be reported to?
SABRE
Under what haemoglobin level is transfusion usually indicated?
70g/L
What 3 things to remember about transfusion
Right blood
Right patient
Right time
Common allergic reaction symptoms patients may get after having a transfusion
Skin rashes
Fever
Dyspnoea
How long does a platelet or plasma transfusion take to give?
Around 30 minutes to an hour
Reasons for red cell transfusion
Surgery / accident leading to blood loss
To treat anaemia
Treatment of cancer / leukaemia
Reasons for a platelet transfusion
To increase the number of platelets in the blood
To replace the platelets which are not working properly
What does plasma look like when it is going to be transfused? And what does it contain?
Pale yellow liquid
Red cells, white cells and platelets, also clotting factors
What does cryoprecipitate contain?
More than one clotting factor called fibrinogen
Once you have had a transfusion, what are you no longer able to do? Why is this?
Donate blood
Precaution against vCJD transmission
What does irradiation do to the blood?
Depleted in T lymphocytes
Who is at risk of transfusion assosiated graft vs host disease (TA-GvHD)?
Transfusions from family members / tissue type matched donors
Those born with immune system disorders
Those with a weakened immune system due to Hodgkins disease / treatment with certain drugs / bone marrow or stem cell transplant
Receiving chemotherapy drugs such as fludarabine
Unborn babies and babies needing exchange transfusions
Why do plasma products such as FFP, cryoprecipitate, anti D, albumin and immunoglobulin not need irradiated?
They do not cause TA-GvHD
What complementary markers tests are done for every donation?
Syphillis HIV Hep B Hep C HTLV 1/2 Hep E
What is a window period?
The period of which between someone is infected to when it is detectable
What do complementary tests now look for in the blood? Why?
Tend to look for antibodies instead of antigens
Antibodies have a shorter window period than antigens
What does vCJD stand for?
Variant CJD
What is taken from one donation?
Red cells
Pooled platelets
FFP
Apheresis platelets
What are pooled platelets?
Plasma and platelets from 4 donations
What are apheresis platelets?
Take out platelets and give the donor back the rest of their blood
How are apheresis donors picked?
Donate regularly
Multiple -ve screening tests
ABO and rheus groups
What happens if red cells go out of temp range for 30 minutes?
Need to be used or discarded
What must be done when storing pooled platelets?
They must be kept constantly moving
What is the top layer of cryoprecipitate more concentrated for?
Clotting factors
What is FFP more concentrated for?
Fibrinogen
What does all of group O have?
H substance
How old are you when you start to produce your own blood antibodies?
3 - 4 months
How many binding sites does the IgG antibodies have?
2
How many binding sites does the IgM antibodies have?
5
How are the IgG antibodies destroyed?
Spleen etc
How are IgM antibodies destroyed?
Destruction in the veins by cross linking (DIC)
What group is the universal plasma donor?
AB
What blood group is the go to group for FFP?
A group
What blood group is hard to get for FFP?
AB
What ways do you get exposure to something foreign to stimulate antibodies?
Pregnancy
Transfusion
What % of the population are Rheusus D +ve and -ve?
85% = +ve 15% = -ve
Why can RhD -ve be transfused to Rh +ve patients?
As no foreign antigen so no antibody stimulated
What blood group can be transfused to all patients no matter what blood group they are?
O RhD negative
What does a second sample blood policy reduce?
Wrong blood in tube incidents
Who is the second sample blood policy for?
Non urgent requests
1st time blood component request
> 12 months old
How long should there ideally be between the two blood samples?
10 minutes
How does the second sample policy not refer to?
Urgent
Infants up to 12 months
Patients whose blood groups are already known to the lab
The 8 main blood groups
A + A - B + B - AB + AB - O + O -
Give examples of who would be given irridated blood
Granulocyte transfusions
IU transfusions
Neonates up to 28 days post expected date of delivery
Bone marrow / stem cell transplants
Immunocompromised (e.g. chemo or congenital)
Patients with / previous Hodgkins disease
Hb transfusion threshold
Without ACS - 70 g/L
With ACS - 80g/L
In patients who are not currently bleeding or about to undergo a procedure, a platelet transfusion should be performed if the plaelets fall to below what level?
10 x10^9/L
What conditions would a platelet transfusion have an increased risk of death?
Thrombotic thrombocytopenic purpura
Heparin induced thrombocytopenia
Autoimmune thrombocytopenia
Chronic bone marrow failure
What platelet count should a platelet transfusion be offered to a patient if they are actively significantly bleeding?
< 30 x10^9
What do platelets have an increased risk of compared to other types of blood product?
Bacterial contamination
What is the universal donor of FFP?
AB RhD negative
What is used to reverse the effects of anticoagulation in an emergency when the patient has a head injury or severe bleeding?
Vitamin K AND
Prothrombin complex concentrate
Treatment of acute haemolytic transfusion reaction
Generous fluid resuscitation (saline)
Termination of the transfusion
Treatment of post transfusion purpura
High dose immunoglobulin therapy
Treatment of allergic transfusion reaction
IM adrenaline, corticosteroids and supportive care
Bronchodilators
What causes acute haemolytic transfusion reaction?
Mismatch of blood group (ABO) which causes massive intravascular haemolysis
Usually the result of RBC destruction by IgM-type antibodies
Presentation of acute haemolytic transfusion reaction
Symptoms begin minutes after transfusion Fever Abdominal pain Chest pain Agitation Hypotension
Complications of acute haemolytic transfusion reaction
DIC
Renal failure
Pathology of non haemolytic febrile reaction
Due to white blood cell HLA Abs
Often the result of previous sensitisations by pregnancies or transfusions
Treatment of non haemolytic febrile reaction
Paracetamol
Pathology of anaphylaxis / allergic reaction post transfusion
Hypersensitivity to components within the transfusion
Presentation of allergic reaction / anaphylaxis post transfusion
Within mins of starting
Severity can range
- urticaria to anaphylaxis with hypotension, SOB, wheezing, stridor or angioedema
Features of TRALI
Development of hypoxaemia / ARDS within 6 hours of the transfusion Hypoxia Pulmonary infiltrates on X ray Fever Hypotension
Presentation of TACO
Pulmonary oedema
HTN
When can IV iron be used?
Patients with iron deficiency anaemia prior to surgery when oral iron cannot be tolerated or the time interval is too short
What is the major criteria to determine if the use of cryoprecipitate is needed in bleeding?
Low fibrinogen level
What is the major constituent of cryoprecipitate?
Factor VIII
