Blood transfusion COPY Flashcards
What is the probalem with givign RhD–ve blood to an RhD +ve patient?
Sensitisation –> once it is okay, but can cause formation of anti-D
–> problematic in pregnancy or future transfusion
When is an antibody screen in blood groups done?
how and why?
1-3% of people have additional antibodies (outside RBO) (risk factor: several previouy transfusion )
Therefore:
IAT: INDIRECT ANTIGLOBULIN TECHNIQUE
Done before every transfusion –> (Screen: S of G&S)
IAT: bridges red cells coated by IgG, which can’t themselves bridge 2 red cells – to form a visible clump. Takes 30 mins’ incubation at 37°C
What is an electronical crossmatch?
When can that be done?
Based on data on blood products and antibody testing, plasma are never physically cross -matched
Can be done with recipient who do not have any antbodies on antibody screen
–> once positive: serological crossmatch needs to be done
How and when are serological crossmatches done?
Usually done if any antibodies positive – >
incubation of donor + recipeint blood for 30-40 minutes
What are the main pillars of Patient Blood Management?
Generally used to optimise blood and how it can be managed
What are the indications for transfusion or RBC?
How is it usually transfused (time and dose)
Before: Treat Iron/Folate/B12 deficiency first unless active bleeding
**Thresholds **
* Most guidelines suggest a threshold of 70g/l if asymptomatic; 80g/l if symptomatic (post-chemo: >80)
- Higher threshold of up to 90-100g/l for patients with coronary heart disease
Others
* Blood Loss: >30% of total blood
How
* Only transfuse one unit at a time unless active bleeding
- Can be transfused “stat” but routinely would be 2-3 hours
What Red cells can be given to what blood groups ?
How are they stored and how should they be given?
Give ABO/D compatible
Group O (negative) in emergency
Stored at 4°C for 35 days
Must be transfused within 4 hours of leaving fridge
Transfuse 1 unit RBC over 2-3 hours
Does ABO and D compatability need to be considered with platelet transfusion?
How are platelet transfusion stored and given?
ABO/D antigens weakly expressed –> **must be ABO matched **
Should be Rhesus D compatible
**Stored at 20°C for 7 days (higher risk of infection) **
Transfuse 1 unit of platelets over 20-30 minutes
What are the indications for Platelet transfusions?
- Any active bleeding / consumption (TTP, DIC, HIT)
- Consumptive disorders e.g. TTP, DIC, HIT
* Do not transfuse unless actively bleeding (plts will be destroyed and transfusion is ineffective) - If massive RBC transfusion (>75 consider transfusion to balance platelets))
- Reduced production e.g. leukaemias
* Transfuse when under 10bn/litre
Higher threshold of 20 in sepsis
* Pre-procedure: Various thresholds depending on procedure
- Prevent Bleeding in surgery
* under 50 (can be higher on vary on site (highest thresholds for eye / brain)
What are the components of FFP?
Plasma, including** all coagulation factors** and plasma proteins
All cellular components are removed from the transfusion product
Unit volume: ∼200–300 mL
What ABO / D compatibiltiy must be considered when giving Cryoprecipitate or FFP?
Why?
RBO must be matched (plasma will/ might still contain antibodies)
D is not important –> does not contain Red cells, therefore sensitisation is extremely rare
What are the indications of giving FFP?
How is it stored and how is it given?
Coinsider using Vitamin K first if appropriate
–> Given for clotting (Pt and APTT abnormalities)
- Do not use unless patient is bleeding or undergoing a procedure e.g. surgery
- Dose depends on patient weight, INR and target INR
- Needs 30 minutes to thaw out first (stored at -24-35 °C for 24-36 months
What are the components of Cryoprecipitate
Has higher Fibrinogen than FFP –>
Clotting factors (fibrinogen, factor VIII, factor XIII), vWF, and fibronectin
What are the indications for giving cryoprecipitate?
- Bleeding associated with fibrinogen deficiency (e.g., due to DIC, liver disease): typically performed if serum fibrinogen is < 100–150 mg/dL
- Alternative therapy for deficiencies in clotting factors, including vWF, factor VIII, and factor XIII
What are the indications for administration of CMV negative blood?
Why?
only required for intra-uterine /neonatal transfusions and
–> for elective transfusion in pregnant women (baby in-utero is exposed to maternal transfusion)
What are the indications for administration of irradiated blood?
Irradiation: kills of more potential infections + donor lymphocytes
Required for highly immunosuppressed patients, who cannot destroy incoming donor lymphocytes: which can cause (fatal) transfusion associated graft versus host disease (TA-GvHD)
What are the indicatins of administration of Washed platelts?
red cells and platelets are only given to patients who have severe allergic reactions to some donors’ plasma proteins (makes extra-sure that less donor’s plasma proteins are there)
But adds 4-5h to transfusion
How can adverse reactions to blood transfusions be classified?
Acute under 24h
Delayed >24h
What are the acute adverse transfusion reactions that occur <24h post-transfusion?
- Acute haemolytic (ABO incompatible)
- Allergic/anaphylaxis
- Infection (bacterial)
- Febrile non-haemolytic
- Respiratory - mainly 2:
1. Transfusion associated circulatory overload (TACO)
2. Acute lung injury (TRALI)
What are the delayed adverse transfusion reactions that occur >24h post-transfusion?
- Delayed haemolytic transfusion reaction (antibodies)
- Infection : viral, malaria, vCJD (all very rare)
- TA-GvHD
- Post transfusion purpura
- Iron overload
What are early signs of an acute transfusion reaction?
How are they monitoried
Can be many signs, incl. rise in temp and pulse
fall in BP
–> monitoring done via obs after first 15 min
–> hourly after until transfusion is finished
What is the most common acute adverse reaction to a transfusion?
How is it detected?
Most common: **Febrile non-haemolytic transfusion reaction
** (1 in 900 transfusions)
Rise in temperature of ≤1°C without circulatory collapse
* Caused by release of cytokines by leukocytes in donor plasma due to storage (cytokines leak)
Management
* Stop or slow-down transfusion
* may need to treat with
paracetamol
* Prevention: use of leukodepleted blood products
What are the clinical symptos and signs of allergic reaction to blood products?
What should be done?
Symptoms of anaphylaxis –> IgE mediated transfusion reaction (1 in 30.000)
Symptoms occur within minutes
* Risk increases in patients with IgA deficiency (as most commonly donor IgA is allergen –> consider IgA negative blood for patietns with IgA deficiency)
Management
1. Stop transfusion
2. Anaphylaxis protocol
What are the clinical symptoms and signs of an ABO mismatch to blood products?
What should be done?
Due to ABO or other mismatch (incidence 1 in 200.00 most commonly due to sampling error)
Rapid onset during transfusion or up to 24h after transfusion IgM-mediated reaction
* Shock: fever chilld, hypotension, tachycardia
* Haemolysis: jaundice, dyspnoea, chest pain
* Can progress to: DIC, Shock, Renal failure
What are the two respiratory acute adverse reactions to blood products?
Which one is the most common and what are the signs + symptoms?
TACO more common - transfusion associated circulatory overoad –> essentially presents as fluid overload and pulmonary oedema
* wihtin 6 hours of infusion
* Resp disress
* Differentiating feautre: TACO presents in patients with pre-existing heart failure /oedema (and symptoms: e.g. increased JVP)
(if at high risk –> think about diuretic administration pre-transfusion)
The other is **TRALI **- Transfusion-related acute lung injury
* Similar symptoms to TACO
* Abscence of heart failure –> non-cardiogenic pulmonary oedema (immune-mediated)
How does bacterial contamination of blood products present as an acute adverse reaction to blood products?
Symptoms occur within minutes to hours
* More commonly occurs with platelet transfusion
* due to production of endotoxins –> can lead to quick collapse
What is TRALI?
Transfusion-related acute lung injury
Symptoms similar to TACO
* Caused by interaction with anti-HLA antibodies in donor blood with recipient
* Transfusion-related acute lung injury
* Abscence of heart failure –> non-cardiogenic pulmonary oedema (immune-mediated)
What is delayed haeolytic transfusion reaction?
Explain the pathophysiology
Occurs within 1 week of transfusion in 1 in 22.000 transfusions
IgG mediated response to foreign blood products –> usually in patients who have recieved previous transfusions and have formed allo-antibodies against minor blood proteins –> binding of alloantibodies to donor RBCs causing extravascular hemolysis
Presentation:
* often asymptomatic
* otherwise: mild symptoms (fever, jaundice, anaemia, chest, abdomen or back pain)
How does Delayed Haemolitc transfusion reaction present?
how do you test for it?
Haemolysis screen
* Bilirubin
* LDH
* Retics
* Hb
* DAT (positive)
* Haemoglobinuria over few days
Test U&Es – as can cause renal failure
Repeat G&S for ? new antibody
What is Transfusion Associated Graft versos host disease?
What is the pathophysiology?
How do you prevent it?
Rare reaction to blood transfusion
Normally: donors blood lymphocytes are destroyed, but in very immunosuppressed patients: donor lymphocytes are not destroyed
–> Lymphocyte-mediated graft vs. host disease
Prevention: use irradiated blood products in very immunosuppressed patients (depleted
lymphocytes)
Presentation: Symptoms include diarrhoea, liver failure, skin desquamation and bone marrow failure
But: always fatal
What tis post-transfusion purpura?
How common is it, how is it treated?
- Relatively rare transfusion reaction
- Due to previous sensitisation to platelt antigens –> mainly in women with multiple pregnancies or multiple blood transfusions
–> Antibody formation against donor platelets (+ destructions of own platelts, unknown why)
Appears 7-10 days post transfusion
* usually resolves in 1-4 weeks, but can cause significant bleeding
Management
* IvIG
*
What is Haemolytic disease of the Newborn?
IgG antibodies against Rhesus factor (from a rh- mother sensitised to D carrying a Rh+ve baby)
–> crossing of IgG antibdoies over placenta
–> destruction of fetal blood
–> presents as
* foetal anaemia
* Haemolytic disease of newborn (anaemia plus high bilirubin - which builds up after birth as no longer removed by placenta)
What are the clinical features of haemolytic disease of the newborn?
- Neonatal anemia
- Hepatosplenomegaly
- Neonatal jaundice
- Usually present at birth or manifests within the first 24 hours of life
- In Rh incompatibility, unconjugated bilirubin levels may be dangerously high, causing kernicterus.
- Hypoxia
- Prematurity
- Scattered petechiae (rare but associated with poor prognosis)
How would you manage pregnancies if mother already has anti-d antibodies formed?
- Monitor fetus for anaemia – MCA Doppler ultrasound
- Deliver baby early, as HDN gets a lot worse in last few weeks of pregnancy
- If severe: intrauterine blood transfusions
How does anti-D to prevent maternal blood sensitisation given in pregnancy work?
RhD positive (fetal) red cells get coated with anti-D Ig and then they get removed by the mother’s reticulo-endothelial system (spleen) before they can sensitise the mother to produce anti-D antibodies
