Blood transfusion COPY Flashcards

1
Q

What is the probalem with givign RhD–ve blood to an RhD +ve patient?

A

Sensitisation –> once it is okay, but can cause formation of anti-D

–> problematic in pregnancy or future transfusion

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2
Q

When is an antibody screen in blood groups done?

how and why?

A

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

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3
Q

What is an electronical crossmatch?

When can that be done?

A

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

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4
Q

How and when are serological crossmatches done?

A

Usually done if any antibodies positive – >
incubation of donor + recipeint blood for 30-40 minutes

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5
Q

What are the main pillars of Patient Blood Management?

A

Generally used to optimise blood and how it can be managed

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6
Q

What are the indications for transfusion or RBC?

How is it usually transfused (time and dose)

A

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
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7
Q

What Red cells can be given to what blood groups ?

How are they stored and how should they be given?

A

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

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8
Q

Does ABO and D compatability need to be considered with platelet transfusion?

How are platelet transfusion stored and given?

A

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

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9
Q

What are the indications for Platelet transfusions?

A
  1. Any active bleeding / consumption (TTP, DIC, HIT)
  2. Consumptive disorders e.g. TTP, DIC, HIT
    * Do not transfuse unless actively bleeding (plts will be destroyed and transfusion is ineffective)
  3. If massive RBC transfusion (>75 consider transfusion to balance platelets))
  4. Reduced production e.g. leukaemias
    * Transfuse when under 10bn/litre

Higher threshold of 20 in sepsis
* Pre-procedure: Various thresholds depending on procedure

  1. Prevent Bleeding in surgery
    * under 50 (can be higher on vary on site (highest thresholds for eye / brain)
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10
Q

What are the components of FFP?

A

Plasma, including** all coagulation factors** and plasma proteins

All cellular components are removed from the transfusion product

Unit volume: ∼200–300 mL

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11
Q

What ABO / D compatibiltiy must be considered when giving Cryoprecipitate or FFP?
Why?

A

RBO must be matched (plasma will/ might still contain antibodies)

D is not important –> does not contain Red cells, therefore sensitisation is extremely rare

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12
Q

What are the indications of giving FFP?

How is it stored and how is it given?

A

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
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13
Q

What are the components of Cryoprecipitate

A

Has higher Fibrinogen than FFP –>

Clotting factors (fibrinogen, factor VIII, factor XIII), vWF, and fibronectin

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14
Q

What are the indications for giving cryoprecipitate?

A
  • 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
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15
Q

What are the indications for administration of CMV negative blood?

Why?

A

only required for intra-uterine /neonatal transfusions and

–> for elective transfusion in pregnant women (baby in-utero is exposed to maternal transfusion)

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16
Q

What are the indications for administration of irradiated blood?

A

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)

17
Q

What are the indicatins of administration of Washed platelts?

A

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

18
Q

How can adverse reactions to blood transfusions be classified?

A

Acute under 24h
Delayed >24h

19
Q

What are the acute adverse transfusion reactions that occur <24h post-transfusion?

A
  • 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)
20
Q

What are the delayed adverse transfusion reactions that occur >24h post-transfusion?

A
  • Delayed haemolytic transfusion reaction (antibodies)
  • Infection : viral, malaria, vCJD (all very rare)
  • TA-GvHD
  • Post transfusion purpura
  • Iron overload
21
Q

What are early signs of an acute transfusion reaction?

How are they monitoried

A

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

22
Q

What is the most common acute adverse reaction to a transfusion?
How is it detected?

A

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

23
Q

What are the clinical symptos and signs of allergic reaction to blood products?

What should be done?

A

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

24
Q

What are the clinical symptoms and signs of an ABO mismatch to blood products?

What should be done?

A

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

25
Q

What are the two respiratory acute adverse reactions to blood products?

Which one is the most common and what are the signs + symptoms?

A

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)

26
Q

How does bacterial contamination of blood products present as an acute adverse reaction to blood products?

A

Symptoms occur within minutes to hours
* More commonly occurs with platelet transfusion
* due to production of endotoxins –> can lead to quick collapse

27
Q

What is TRALI?

A

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)

28
Q

What is delayed haeolytic transfusion reaction?
Explain the pathophysiology

A

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)

29
Q

How does Delayed Haemolitc transfusion reaction present?
how do you test for it?

A

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

30
Q

What is Transfusion Associated Graft versos host disease?
What is the pathophysiology?
How do you prevent it?

A

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

31
Q

What tis post-transfusion purpura?
How common is it, how is it treated?

A
  • 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
*

32
Q

What is Haemolytic disease of the Newborn?

A

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)

33
Q

What are the clinical features of haemolytic disease of the newborn?

A
  • 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)
34
Q

How would you manage pregnancies if mother already has anti-d antibodies formed?

A
  • 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
35
Q

How does anti-D to prevent maternal blood sensitisation given in pregnancy work?

A

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