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
