36 - Blood transfusion Flashcards Preview

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Flashcards in 36 - Blood transfusion Deck (62):
1

Whole blood can be separated into what components?

RBCs
Platelets
Plasma

2

What process is done to go from whole blood to RBC?

Leucodepletion

3

What can be done to plasma after separation from whole blood?

Fresh frozen plasma

Cryoprecipitate

Fractionation

4

What products would there be after fractionation of plasma

Factor concentrates (FVIII, FIX, prothrombin)
Albumin
Immunoglobulin

5

Facts about 1 unit RBC

4 degrees storage for 35 days

Most plasma removed for high [RBC]

Usual transfusion time 90mins to 3 hours

4 hour limit from removal from cold storage to end of transfusion

6

Transfusion threshold (trigger) definition

Lowest [Hb] that is not associated with symptoms of anaemia

7

Mechanisms of adaption to anaemia

Increase CO
Increased cardiac artery blood flow
Increased oxygen extraction
Increase RBC 2,3 DPG
Increase production of EPO
Increase erythropoiesis

8

Production of EPO and an increase in erythropoiesis occurs when and by which organ?

After longterm, chronic anaemia

The kidneys

9

Alternatives to RBC transfusions

Give iron
Give B12 and folate
Erythropoietin treatment for patients with renal disease

10

When to give RBCs

Think about necessity - class III on BCSH is 30-40% reduction in blood volume - start thinking about it here.

Necessary >40% (at class IV)

11

Management of chronic anaemia

Symptomatic relief
Improvement of quality of life
Prevention of ischaemic organ damage

12

Threshold levels for chronic anaemia

80-100g/dl

13

Thrombocytopenic definition

Deficiency in platelets in the blood

14

Iron overload - at risk group

Problem with patients on regular transfusions (thalassaemias)

Our aim with thalassaemia is to suppress endogenous erythropoiesis

15

Complications of iron overload

Cardiomyopathy
Liver failure

16

Iron chelation is to

Reduce the complications of iron overload

17

Haemochromatosis definition

Iron overload

18

Platelet storage

Stored at room temperature (22 degrees)
Shelf-life 5 days from collection

19

How many donations to one patient?

4

20

Usual transfusion time for platelets

30 mins/unit

21

Causes of thrombocytopenia

Massive haemorrhage
Bone marrow failure
Prophylaxis for surgery

22

Contraindications for thrombocytopenia

Heparin induced thrombocytopenia & thrombosis

Thrombotic thrombocytopenic purpura

23

Fresh frozen plasma - storage

-30 degrees for 24 months

Thawed immediately before use (20-30 mins)

24

FFP - usual transfusion time

30 mins/unit

25

Indications for FFP transfusion

Coagulopathy with bleeding/surgery

Massive haemorrhage

Thrombotic thrombocytopenic purpura

26

When not to transfuse FFP

Warfarin reversal

Replacement of single factor deficiency

27

Special requirements for transplant

CMV free
Children

28

Tests to do on patients before transfusion

ABO and Rh(D) group
Patient's plasma screened for Ig against other clinically significant blood group antigens (compare vs panel of RBCs - if -ve no further testing)

29

Crossmatching testing

Aliquots of donor red cells mixed with normal and see if reaction (agglutination or haemolysis)

30

If there is a reaction to crossmatch test what does that mean? what can happen?

RBC units in compatible
Risk of acute haemolysis

31

Acute transfusion reactions

Immunological - acute haemolytic transfusion reaction ABO incompatibility
Allergic/anaphylactic reaction
TRALI - transfusion-related acute lung injury

Non-immunological - bacterial contamination
TACO (transfusion associated circulatory overload)
Febrile non-haemolytic transfusion rxn

32

Delayed transfusion rxns

Immunological - transfusion-associated graft-versus-host disease (TA-GvHD)
Post transfusion purpura

Non-immunological - transfusion transmitted infection (TTI) viral or prion

33

Time scale for acute / delayed transfusions rxns

24hr delayed

34

What is the acute haemolytic reaction-ABO incompatibility? And what is it frequency?

1:25k

1. Release of free Hb
2. Hb deposition in distal renal tubules = acute liver failure
3. stimulation of coagulation results in microvascular thrombosis
4. stimulates cytokine storm
5. NO released resulting in generalised vasoconstriction

35

Acute haemolytic reaction - ABO incompatibility - reactions timings and % fatality

Severe reactions during transfusion - first 15mins

Mild occur later before end of transfusion

Fatal in 20-30%

36

Acute haemolytic reaction - ABO incompatibility - signs and symptoms

Fever and chills
Back pain
Infusion pain
Hypotension/shock
Haemoglobinuria (in anaesthetised patients)
Increased bleeding (DIC)
Chest pain
Sense of 'impending death'

37

Delayed haemolytic reaction - time of onset

3-14 days following transfusion

38

Delayed haemolytic reaction - clinical features

Fatigue
Jaundice
Fever

39

Delayed haemolytic reaction - lab findings

Drop in Hb
Increased LDH
Increased indirect bilirubin

Direct antiglobulin test = positive

40

Delayed haemolytic reaction - why does it occur

Delayed haemolytic reaction is due IgG against RBC antigens than ABO

The antibodies are formed after the transfusion

41

What is Coomb's test?

Anti-human globulin test to detect incomplete IgG antibodies

42

Steps in Coomb's test

1. RBCs coated with IgG antibody e.g. anti-Rh in a Rh positive patient
2. Anti-human globulin test (AHG) added
3. Visible agglutination

43

Transfusion related acute lung injury - rate of fatalities, why

5-10% fatal
Donor has antibodies to recipient's leucocytes
Associated with transfusion of plasma rich components (platelets, FFP)

44

Transfusion related acute lung injury - antibodies of donor

anti-HLA
anti-HNA

45

Transfusion related acute lung injury - how does it damage lungs?

Activated WBC lodge in pulm. capillaries

Release substances that cause endothelial damage and capillary leak

46

TRALI - steps for diagnosis

1. Presence of acute lung injury = hypoxia, bilateral chest x-ray infiltrates, absence of circulatory overload

2. occurs within 6 hrs of transfusion

47

TRALI - treatment

Supportive

Mild = supplemental oxygen
Severe = mechanical ventilation & ICU support

Most recover between 72-96 hours

48

TRALI - lab investigations

Donor tested for HLA and granulocyte antibodies

Recipient tested for expression of neutrophil antigens

49

Transfusion-associated circulatory overload (TACO) - presentation

Symptoms: sudden dyspnea
Orthopnoea
Tachycardia
Hypertension
Hypoxemia

Signs:
Raised BP
Elevated jugular venous pulse

50

Transfusion-associated circulatory overload (TACO) - risk factors

Elderly
Small children

Patients with poor:
Left ventricular function
Increased volume of transfusion
Increased rate of transfusion

51

Comparing TRALI with TACO - type of component

Usually plasma or platelets

Any

52

Comparing TRALI with TACO - BP

Lower in TRALI

Often raised in TACO

53

Comparing TRALI with TACO - temperature

Often raised in TRALI

Normal in TACO

54

Comparing TRALI with TACO - Echo

Normal

Abnormal

55

Comparing TRALI with TACO - diuretic use

Worsens

Improves

56

Comparing TRALI with TACO - fluid loading

Improves

Worsens

57

Allergic rxns to transfusion

Urtical rash ± wheeze
Often not severe
Hypersensitive to random plasma protein

58

Anaphylaxis

Severe, life-threatening rxn soon after transfusion

Wheeze/asthma, higher pulse, low BP (shock)

Laryngeal/facial oedema

59

Anaphylaxis - investigations

Quantification of IgA, testing for anti-IgA antibodies

60

Febrile non-haemolytic transfusion reactions (FNHTR) - onset, presentation

During or soon after transfusion

Fever ± shakes/rigors
± upped pulse

Unpleasant but not life threatening

61

Febrile non-haemolytic transfusion reactions (FNHTR) - why?

Cytokine that accumulate during storage of blood components

Less of an issue since leucodepletion

Self-limited rxn

62

Febrile non-haemolytic transfusion reactions (FNHTR) - what to do

Discontinue transfusion until you exclude 'wrong blood' or bacterial infection

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