Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Haematology > 11. Blood transfusion > Flashcards

11. Blood transfusion Flashcards

1
Q

What is the shelf life of blood?

A

5 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How much blood can you take from a donor?

A

1 pint (1 unit) max, every 4 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When is blood used as a treatment?

A
  • When there is no safer alternative
  • During a massive bleed
  • Anaemic patients - if iron/B12/folate not appropriate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which red cells are H antigens found on?

A

All red cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are A and B antigens formed?

A

• Adding sugar residues to a common glycoprotein and fucose stem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which antigens do group O people have?

A

Only H stem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which enzymes do the ABO blood groups code for?

A
  • A gene - N-acetyl galactosamine transferase
  • B gene - galactose transferase
  • A and B - co-dominant (both genes => both chains)
  • O - recessive: may carry O and A/B but A/B will be dominant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why can an ABO incompatible transfusion be fatal?

A
  • Patient has corresponding antibody e.g. group A has anti-B antibodies, group O has anti-A and B antibodies
  • IgM interact
  • Activation of complement cascade
  • Haemolysis of red cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you cross-match blood groups?

A
  • Mix patient serum with donor red cells
  • Agglutination=> incompatible
  • Due to antibody interacting the red blood cell antigens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the most important RH blood grouping?

A

• RhD positive (D antigen)
- presence is dominant
• RhD negative (no D antigen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When are antibodies made against antigens in blood grouping?

A

• Antibodies against antigens we lack are made from birth in ABO
• Made from first exposure for all other blood grouping systems - including RhD
• RhD negative can only make anti-D antibodies after exposure to RhD antigens
- by transfusion
- during pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What type of immunoglobulins are anti-D antibodies?

A

IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of antibodies does an RhD positive person produce after exposure to RhD negative blood?

A

None

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

A RhD negative person is exposed to RhD positive blood, when and how will they react?

A

• Won’t react first time
• React next time given blood
- new anti-D antibodies interact with second transfusion of RhD positive blood
• Won’t cause death as IgG doesn’t go through the complement cascade
• Slower, extravascular haemolysis
• Still harms the patient - jaundice, free Hb from red cell lysis damages renal tubules => renal failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When is there a danger to the foetus in relation to the RhD blood group?

A
  • RhD negative mother has transfusion of RhD positive blood
  • Mother makes anti-D antibodies
  • If foetus is RhD positive, mother’s IgG can cross the placenta => haemolysis of foetal red cells
  • If severe: hydrops fetalis (severe oedema) => death
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What blood type is used as emergency blood when the patient’s blood type is not known?

A

O negative

17
Q

How will a baby with hydrops fetalis be affected if it makes it to birth?

A
  • Anaemia may still be a problem
  • Bilirubin needs to be broken down by liver (previously dealt with by mother)
  • Liver can’t cope
  • Bilirubin crosses BBB and causes brain damage
  • Death
18
Q

How is blood given to a patient?

A
  • 1 unit of blood collected into a bag with anticoagulant
  • No longer give whole blood - patient doesn’t need all of it and some components degenerate quickly if whole
  • Split into: red cells, plasma (antibodies and coagulation factors), buffy coat (WBCs, platelets)
  • Red cells are concentrated and plasma is removed - avoid fluid overload
  • Split by centrifuging
19
Q

At what temperature are red cells stored?

A

• 4’C
• Rarely frozen
- done for rare groups
- poor recovery on thawing - lose up to half the dose

20
Q

How is fresh frozen plasma stored and adminstered?

A
  • Frozen to preserve coagulation factors
  • Stored at -30’C within 6 hours of donation, shelf life of 2 years
  • Thaw approx. 20-30mins before using it
  • Give ASAP as coagulation factors degenerate at room temperature
  • Dose dependent on patient’s weight: usually 3 units
  • Blood group important - may cause a bit of haemolysis
21
Q

When do we give fresh frozen plasma?

A
  • Patients who are bleeding due to abnormal coagulation factors
  • Patient with abnormal coagulation test results
  • Reversal of warfarin e.g. for urgent surgery
  • Other conditions occasionally
22
Q

What is cryoprecipitate and when is it used?

A
  • Residue that remains when you thaw FFP slowly (at 4-8’C overnight)
  • Precipitate at the bottom
  • Contains fibrinogen and factor 8
  • Stored the same as FFP
  • Standard dose - from 10 donors = 2 packs
  • Used in massive bleeding events
  • People with very low fibrinogen
  • Rare conditions e.g. hypofibrinogenaemia (hereditary)
23
Q

How are platelets stored?

A

• 1 pool from 4 donors, or 1 donor by apheresis (cell separator machine)
• Stored at 22’C, shelf life of 5 days (risk of bacterial infection)
• Blood group important
- low levels of ABO antigens on platelets
- RBC contamination can cause RhD sensitisation

24
Q

When do we give platelets to a patient?

A
  • Mostly haematology patients with bone marrow failure
  • Massive bleeding or acute DIC
  • Very low platelets + patient needs surgery
  • Cardiac bypass surgery + patient is on anti-platelet drugs
  • 1 pool usually enough
25
Q

What fractionated products are used in blood transfusions?

A

Factor 8 and 9
• haemophilia A and B
• Factor 8 for vW disease
• heat-treated - viral inactivation

Immunoglobulins
• IM - specific: tetanus, anti-D, rabies
• IM - normal globulin, broad mix of antibodies from the pop. (e.g. hep A virus)
• IV - broad mix of antibodies, pre-operative patients with ITP or AIHA

Albumin
• 4.5% - useful in burns (loss of fluid), probably overused though
• 20% - severe liver and kidney conditions - kidney tubules become porous => proteins excreted => poor oncotic pressure

26
Q

Which infections must be tested for before using blood for donation?

A
  • Hep B
  • Hep C
  • HIV
  • Syphilis
  • HTLX
  • Hep E
  • Some also test for CMV
27
Q

How reliable are tests for infections in blood for donation?

A 
• Not 100% perfect
• Certain infections detectable after a certain amount of time - window period
• Cannot rely on testing
- therefore exclude high risk donors
- use voluntary, unpaid donors
28
Q

Can prion disease variant CJD be transferred by blood transfusion?

A
  • Yes - can lead to death
  • Filtering out the white cells (leucodepletion) can reduce the risk as they are essential for uptake of vCJD into the brain

Haematology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions