Blood transfusions Flashcards
What are the key steps to take before initiating a blood transfusion?
- Wash your hands and don appropriate PPE.
- Request a colleague to assist you with checking the blood transfusion
- Ask the patient to tell you their name and date of birth and then compare this to their bracelet, medical notes and blood compatibility report to ensure they all match exactly.
- Check the blood group and serial number on the blood bag matches the compatibility report.
- Check the expiry date and time on the unit of blood to ensure it has not expired.
- Inspect the blood bag for:
Signs of tampering, leaks, discolouration and clots
How long can blood be out of the fridge for?
Blood out of fridge over 30 mins should be transfused within 4 hours or discarded
How should you administer a blood transfusion?
- Wash your hands and don appropriate PPE (if not done so already).
- Attach the giving set to the blood bag and run some blood through the tubing to expel any air.
- Once all air has been expelled from the tubing, attach the other end of the giving set to the cannula port.
- Set the time the blood should be transfused over (typically 2-3 hours in non-urgent scenarios).
- Dispose of the relevant equipment into a clinical waste bin (including PPE) and wash your hands.
- Document the time and date that the transfusion was started and both you and your colleague will need to sign to confirm all checks were carried out prior to administration.
What is the blood transfusion threshold and Hb target?
Without ACS:
threshold = 70 g/L
target = 70-90g /L
With ACS
threshold = 80 g/ L
target = 80-100 g/ L
How quickly should one unit of red cells be transfused?
emergency = STAT
non urgent = over 90-120 minutes
How should patients be monitored during blood transfusion?
The patient’s baseline obs (including blood pressure, pulse, resp rate and temperature) should be checked at 0, 15 and 30 minutes from the onset of the transfusion.
Observations can then be performed on an hourly basis and again when the transfusion has finished.
Regular observations allow early detection of transfusion reactions
Name the key transfusion reactions
Got a bad unit
G raft vs. Host disease
O verload (TACO)
T hrombocytopaenia
A lloimmunization
B lood pressure instability
A cute haemolytic reaction
D elayed haemolytic reaction
U rticaria / Anaphylaxis
N eutrophilia
I nfection
T ransfusion associated lung injury
Irradiated blood products are required in patients following bone marrow and stem cell transplants for what reason?
to prevent graft versus host disease
(depleted of T lymphocytes)
How is TRALI differentiated from TACO?
hypotension in TRALI vs hypertension in TACO
Which blood product is most likely to cause an iatrogenic septicaemia with a Gram-positive organism?
Platelets - stored at room temperature
The first step in management of any suspected transfusion reaction is what?
stop the transfusion!!!
Fever, abdominal pain, hypotension during a blood transfusion →
acute haemolytic reaction
due to RBC destruction by IgM-type antibodies
Hypotension, dyspnoea, wheezing, angioedema during a blood transfusion →
anaphylaxis
What is the universal donor of FFP?
AB RhD negative blood
What is involved in blood conservation technique?
1.Increase red blood cell mass – e.g. correct iron deficiency
2.Reduce peri-operative blood loss – e.g. op for regional not GA where possible
3.Optimising transfusion practice – allogenic transfusion/ autologous transfusion (cell salvage)
What are the benefits of blood transfusion for a symptomatic anaemic patient?
reduces sx burden e.g. makes patients less tired and SOB
reduces risks of anaemia e.g. cardiovascular risk (worsening LVF or anaemia-induced MI)
What is the difference between a Group and Screen and a crossmatch?
G&S = finding out the blood group
Cross match = assess for reaction of patients serum with the red cells you are going to give them
What is the risk of giving a patient the wrong blood?
causing an acute haemolytic reaction - activated compliment system which causes a systemic inflammatory response
What should you ask in the history for a cancer patient with symptomatic anaemia?
how long have they had symptoms for?
what treatments are they receiving for their cancer and when did they last receive them? (especially things that may cause bone marrow failure)
Any visible blood loss - rectal bleeding, haematuria, bleeding from gums, epistaxis?
What is their diet like? (still can be common things like IDA in cancer patients)
What investigations might you do for a patient presenting with new symptomatic anaemia?
- FBC (incl. MCV)
- reticulocyte count (production issue or destruction issue)
- LFTs - bilirubin for haemolysis
- LDH- burden of haematological disease and cell turnover
- iron, ferritin, transferrin saturation - IDA
- vitamin B12 and folate - megaloblastic anaemia
G&S and crossmatch if they require transfusion
peripheral blood film
bone marrow aspirate / biopsy
What is the function of haptoglobin cells?
haptoglobins carry destroyed haem
low free haptoglobins mean more are bound carrying destroyed red cells - suggests haemolysis
How does haemolytic anaemia present on investigation?
anaemia
reticulocytosis
low haptoglobin
raised lactate dehydrogenase (LDH) and indirect bilirubin
blood film: spherocytes and reticulocytes
How would you confirm diagnosis of an autoimmune haemolytic anaemia?
DCT : Direct Coombs test - looking for antibodies bound to surface of RBCs
In autoimmune haemolytic anaemia there are antibodies e.g. IgG bound to the red cells’ surface that causes them to be destroyed by the spleen
patients can be managed with an anti IgG antibody
Outline the UHL massive haemorrhage protocol
Alert senior staff member that you are activating massive haemorrhage protocol
Give warmed IV crystalloid bolus
Transfuse 4 units red cells if indicated (can use O- blood if required but inform Blood Bank if emergency supplies used)
Attempt to control bleeding
Consider tranexamic acid
Reverse any anticoagulation
Arrange cell salvage where available
Which tests make up a Haemolysis screen?
Increased bilirubin, LDH and reticulocytes
Decreased Haptoglobins - as mops up free Hb
Blood film:
- spherocytes in all causes of haemolysis, this is the prominent feature in AIHA
- red cell fragments (schistocytes) in microangiopathic or mechanical haemolytic anaemia
- Polychromasia (young red cells) if bone marrow able to respond to anaemia
DCT - direct coombs test
- positive in immune causes of haemolysis but negative in non- immune causes
How may haemolytic anaemia be classified?
Hereditary v acquired
Immune v non-immune
Extravascular v intravascular
Give some intravascular causes of haemolysis
mismatched blood transfusion
G6PD deficiency
red cell fragmentation: heart valves, TTP, DIC, HUS
cold autoimmune haemolytic anaemia
Give some extravascular causes of haemolysis
haemoglobinopathies: sickle cell, thalassaemia
hereditary spherocytosis
haemolytic disease of newborn
warm autoimmune haemolytic anaemia
What is warm autoimmune haemolytic anaemia (AIHA)?
the most common type of AIHA
In warm AIHA the antibody (usually IgG) causes haemolysis best at body temperature and haemolysis tends to occur in extravascular sites, for example the spleen
What causes warm AIHA?
idiopathic
autoimmune disease: e.g. SLE
neoplasia
lymphoma
chronic lymphocytic leukaemia
drugs: e.g. methyldopa
How can warm AIHA be managed?
treatment of any underlying disorder
steroids (+/- rituximab) are generally used first-line
What is cold AIHA?
The antibody in cold AIHA is usually IgM and causes haemolysis best at 4 degrees C.
Haemolysis is mediated by complement and is more commonly intravascular
Features may include symptoms of Raynaud’s and acrocynaosis
What causes cold AIHA?
neoplasia: e.g. lymphoma
infections: e.g. mycoplasma, EBV
Give some hereditary causes of haemolysis
Red cell enzymopathies:
* G6PD deficiency
* Pyruvate Kinase deficiency
Abnormal Hb:
* Unstable haemoglobins
* Sickle cell disease
* Thalassaemia
Give some acquired causes of haemolysis
Alloimmune:
HDFN
Incompatible transfusion
Autoimmune:
Warm AIHA (1°, 2° eg CLL, drugs, SLE)
Cold AIHA (mycoplasma, EBV)
Non-immune:
Microangiopathic HA (i.e. TTP or HUS)
Prosthetic heart valves
Sepsis/ DIC
Malaria
If transfusion becomes necessary for AIHA what problems may be encountered?
active antibodies will continually break down blood products
can’t crossmatch blood as antibodies will react with everything
How is haemolysis monitored in the acute and outpatient setting?
daily bloods and then weekly bloods as an outpatient
includes FBC, retics, LFTs and LDH
Give some indications for the use of irradiated blood products
bone marrow transplant / peripheral blood stem cell transplant recipient
due for bone marrow harvest in next 7 days
Hodgkin’s disease (even if cured)
Currently on certain medications incl. Fludarabine
exchange transfusion in neonates and infants up to 6 months
Who needs CMV negative blood?
pregnant women and neonates up to 28 days from EDD
Give indications for red cell transfusion. What dose would you transfuse at?
anaemia, haemorrhage
1 unit unless MHP
consider alternatives e.g. replace haematinics first, cell salvage, EPO
Give indications for FFP transfusion. What dose would you transfuse at?
coagulopathy and bleeding, prolonged APTT and PT , INR >1.5
12-15ml/kg (usually 3-4 bags for an adult)
Give indications for cryo transfusion. What dose would you use?
replace fibrinogen in bleeding patient with coagulopathy
fibrinogen <1.5 or <2 in obstetrics
2 pools
How do patients with low clotting factors versus low platelets present differently?
low clotting factors = bruises or bleeding into joint spaces
low platelets = petechial rash (pinprick), gum bleeding, oral blisters
What is the threshold for platelet transfusion?
<10 - wait till as low as possible because patients quickly make antibodies to platelets and become refractory to tx
What is the maintenance tx for B12 deficiency?
IM Hydroxocobalamin 1mg every 2-3 months
Non-haemolytic febrile reaction is thought to be caused by antibodies reacting with white cell fragments in the blood product and cytokines that have leaked from the blood cell during storage.
How does it present?
How can it be managed?
Fever, chills, more common following platelet transfusion
Mx:
Slow or stop the transfusion
Paracetamol
Monitor
Minor allergic reactions to blood products are thought to be caused by foreign plasma proteins.
How may they present?
How should they be managed?
Pruritus, urticaria
Mx:
Temporarily stop the transfusion
Antihistamine
Monitor
Acute haemolytic reaction occurs when a patient is given ABO-incompatible blood e.g. secondary to human error.
How does it present?
How should it be managed?
Fever, abdominal pain, hypotension
Mx:
Stop transfusion
Confirm diagnosis : check the identity of patient/name on blood product, send blood for direct Coombs test, repeat typing and cross-matching
Supportive care (fluid resuscitation)
Transfusion-associated circulatory overload (TACO) occurs due to excessive rate of transfusion or pre-existing heart failure.
How does it present?
How should it be managed?
Pulmonary oedema, hypertension
Slow or stop transfusion
Consider intravenous loop diuretic (e.g. furosemide) and oxygen
What causes Transfusion-related acute lung injury (TRALI)?
Non-cardiogenic pulmonary oedema thought to be secondary to increased vascular permeability caused by host neutrophils that become activated by substances in donated blood
How does TRALI present?
Hypoxia, pulmonary infiltrates on chest x-ray, fever, hypotension
How should TRALI be managed?
Titrate oxygen, give IV fluids and consider escalation of care
