Brainscape's Knowledge GenomeTM

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


See full index

Principles of Medicine (POM) - Block 2 > ALS4: Blood Transfusion > Flashcards

ALS4: Blood Transfusion Flashcards

1
Q

Why is the ABO system important?

A

Because people have naturally occurring antibodies against any antigen NOT present on own red cells, from birth.

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

What immunoglobulin class are the antibodies in the ABO system?

A

IgM

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

What is the danger of incompatible blood being transfused?

A

The antibodies are reactive at 37ºC and capable of fully activating complement, so are able to cause potentially fatal haemolysis (destruction of red cells) if incompatible blood is transfused.

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

Describe Group A blood type (antibodies in plasma, antigens in RBC)

A

Antibodies in plasma = Anti-B

Antigens in RBCs = A antigens

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

Describe Group B blood type (antibodies in plasma, antigens in RBC)

A

Antibodies in plasma = Anti-A

Antigens in RBCs = B antigens

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

Describe Group AB blood type (antibodies in plasma, antigens in RBC)

A

Antibodies in plasma = None

Antigens in RBCs = A + B antigens

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

Describe Group O blood type (antibodies in plasma, antigens in RBC)

A

Antibodies in plasma = Anti-A and Anti-B

Antigens in RBCs = None

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are A and B antigens on RBCs formed?

A

By adding one or another sugar residue onto a common glycoprotein and fucose stem (H antigen) on the red cell membrane.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is special about Group O?

A

Group O has neither A or B sugars – H stem only.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How are antigens determined?

A

By corresponding genes

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

What does the A gene code for?

A

An enzyme that adds N-acetyl galactosamine (galnac) to the common H antigen

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

What does the B gene code for?

A

Enzyme which adds galactose (gal)

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

Which genes are codominant?

A

A and B

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

Which gene is recessive?

A

O

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

Which blood group can be given to anyone in an emergency?

A

Group O negative blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What additional classification do blood groups have?

A

If they are RhD positive or RhD negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the Rh system?

A

Another antigen called antigen D may or may not be present on RBCs. If it is present it is said to be RhD positive blood and if it isn’t present it is RhD negative.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is the presence of antigen D determined?

A

By genes - D gene codes for D antigen on red cell membrane, d gene codes for no antigen and is recessive, Therefore

  • Group RhD negative = dd
  • Group RhD positive = DD or Dd
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What can happen to people who are RhD negative?

A

They can make anti-D antibodies after they are exposed to the RhD antigen - either by transfusion of RhD +ve blood, or in women if pregnant with an RhD positive foetus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What class of antibodies are anti-D antibodies?

A

IgG

21
Q

What are some implications of anti-D antibodies?

A
  1. Future transfusion - patient must have RhD negative blood otherwise anti-D would react with D antigen causing delayed haemolytic transfusion reaction, anaemia etc.
  2. haemolytic disease of newborn - IgG antibodies can cross placenta.
22
Q

What do we need to avoid in terms of the Rh system in blood groups?

A

Avoid sensitisation of RhD negative patients

23
Q

What must be tested before giving a patient a blood transfusion?

A

ABO and RhD blood groups on patient’s red cells.

An antibody screen on patient’s plasma (known as ‘group + screen’

24
Q

Why is an antibody screen performed prior to a blood transfusion?

A

To exclude any clinically significant immune antibodies.

25
Q

How does an antibody screen work?

A

Patient plasma is incubated w/ 2 or 3 diff fully typed ‘screening red cells’ which are known to possess all blood group antigens which matter clinically.

26
Q

What do the results of an antibody screen show?

A

If negative = any donor blood which is ABO and RhD compatible may be given
If positive = antibody must be identified w/use of large panel of red cells. Donor units of blood that lack corresponding blood group antigen are then chosen for cross-matching w/recipient’s plasma prior to transfusion.

27
Q

What group of people is blood collected from in the UK?

A

Volunteer, unpaid donors, who are between 17 - 70 years old. Excludes those with diseases that might make blood donation hazardous for them e.g. cardiovascular, neurological disease or if blood is hazardous for recipient e.g. infections etc.

28
Q

What tests are undertaken on blood donations?

A
  1. Group and screening - ABO + RhD blood group determined, also other Rh blood groups (like C,c, E, e and K blood group are determined on most donations in UK), tested to ensure no clinically significant red cell antibodies present in donor’s plasma
  2. Infection testing,- to maintain safe blood supply test for HIV, hepatitis B, hepatitis C, hepatitis E etc.
29
Q

How much blood is usually collected from a donor into 1 sterile plastic bag containing anti-coagulant?

A

450ml

30
Q

What is 1 unit of blood when talking about blood components and products?

A

Whole blood or blood products from 1 SINGLE DONATION

31
Q

What components of blood are stored separately?

A 
Red cells
Fresh frozen plasma (FFP)
Cryoprecipitate (contains fibrinogen and factor VIII)
Platelet concentrates
Blood products
32
Q

How should red blood cells be stored?

A

4 degrees Celsius in fridge

33
Q

How should platelets be stored?

A

22 degrees Celsius (room temp) constantly agitated

34
Q

How should fresh frozen plasma be stored?

A

-30 degrees Celsius (frozen within 6hrs of donation to preserve coagulation factors)

35
Q

How should cryoprecipitate be stored?

A
  • 30 degrees Celsius like FFP
36
Q

What is the shelf life of red blood cells?

A

5 weeks

37
Q

What is the shelf life of platelets?

A

7 days (risk of bacterial infection)

38
Q

What is the shelf life of cryoprecipitate ?

A

3 years

39
Q

What is the shelf life of fresh frozen plasma?

A

3 years

40
Q

What is the normal dose given of red blood cells?

A

1 unit from 1 donor, fluid plasma removed

41
Q

What is the normal dose given of platelets?

A

1 unit (one pool is usually enough - 4 donations pooled together)

42
Q

What is the normal dose given of cryoprecipitate?

A

standard dose = from 10 donors (5 in a pack)

43
Q

What is the normal dose given of fresh frozen plasma?

A

12-15 ml/kg = usually 3 units (1 unit from one donor = 300ml)

44
Q

Why might a patient need red blood cells?

A

Need Hb

45
Q

Why might a patient need platelets?

A
  • Patients w/bone marrow failure
  • Massive bleeding or disseminated intravascular coagulation
  • Very low platelets + need surgery
  • Cardiac bypass and patient is on anti-platelet drugs
46
Q

Why might a patient need cryoprecipitate?

A
  • Massive bleeding and fibrinogen very low

- Rarely inherited hypofibrinogenemia

47
Q

Why might a patient need frozen plasma?

A
  • Bleeding + abnormal coagulation results (PT, APTT)

- Reversal of warfarin (anticoagulant) e.g. For urgent surgery (if prothrombin complex conc. Not available)

48
Q

What components make up blood products?

A

Large pool of plasma that is fractionated containing:

  • factor VIII and IX
  • immunoglobulins
  • albumin

Principles of Medicine (POM) - Block 2 (12 decks)

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