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Flashcards in Haematology Transfusion Deck (69):
1

Blood Donors

1. Healthy volunteer donor
2. Age 17-70 (no age limit for regular donors)
a. Medically assessed
i. History
ii. Medication
iii. Travel
b. Fingerprick Hb
i. Women >12.5
ii. Men >13.5 g/dl
3. 450 ml collected, up to every 12 weeks

2

Apheresis donation and therapy

• Selective removal of the component required platelets or plasma (occasionally red cells)
• Up to 3 adult doses of platelets/donor visit
• Also used for therapeutic removal of plasma/WBC/platelets

3

Processing

• Leucocyte depletion – reduces WCC reaction to recipiant
• Split into red cells/platelets/Plasma
• Special processes (to order): irradiation, washing, hyper-concentration

4

Blood components available

Plasma
Platelets (Granulocytes) – rare cases
Red cells

5

Plasma

Fractionated plasma proteins – albumin/clotting factors
Fresh frozen plasma (for clotting factors)
Cryoprocipitate – rich in fibrinogen

6

Red cells: Used for

Blood loss
Anaemia

7

Red cells: Storage

In additive solution
• 280+/-60 ml (slightly more concentrated)
• 0.5-0.7 haematocrit
Risk of bacterial infection post refrigeration (only 4hrs transfusion time)

8

Red cells: Shelf life

35 day shelf life at 4 degrees

9

Platelet Concentration: Used for

Thrombocytopenia
Platelet dysfunction

10

Platelet Concentration: Collection process

Pooled from 4-6 donors

11

Platelet Concentration: Apheresis

Single donor

12

Platelet Concentration: Storage

22 +/- 2oC (room temp) for 5 days on an agitator (7 days if bacterial screening)

13

Fresh Frozen Plasma: Used for

Replacement of clotting factors

14

Fresh Frozen Plasma: Storage

Plasma fraction frozen to -30oC
Stored up to 3 yrs
20 mins to defrost
Infuse with 4 hours

15

Fresh Frozen Plasma: Virally inactivation via and used for

Children and if using large volumes:
• Methylene Blue Treatment
• Solvent detergent treatment

16

Cryoprecipitate: Formed

Precipitate formed when defrosting FFP – rich in fibrinogen (Factor 8)

17

Cryoprecipitate: Contain

Rich in fibrinogen
Factor 8
VWF

18

Cryoprecipitate: Used

For fibrinogen supplementation – mostly bleeding patients

19

Cryoprecipitate: Virally

Inactivation (methylene blue) available

20

Fractionated blood products: Prepared from

They are pharmaceutical products
Prepared from pooled plasma from many donors

21

Fractionated blood products: Contain

Albumin
Clotting factor concentrates
Intravenous immunoglobulin
Disease – specific immunoglobulin

22

Hazards of Transfusions

1. Unavailable blood
2. Transfusion transmitted infections
3. Immunological reactions
4. Overloading:
a. Iron
b. Fluid

23

Lack of Blood







WHO:
1. Each year, more than 500000 women die needlessly during pregnancy or childbirth
2. Severe bleeding can kill even a healthy woman with 2 hrs if she is unattended = 44% of maternal deaths in Africa
3. Up to one-fourth of all maternal deaths could be saved by access to safe blood transfusion
4. Also happens in developed worl – usually organisational problems

24

Transfusion transmitted infection: virus

HIV
HBV
HCV
CMV
HTLV1
Parovirus
West Nile Virus

25

Transfusion transmitted infections: Protozoa

Malaria
Trypanosomes
Syphilus

26

Transfusion transmitted infections: Bacteria

Staphylococci (Skin)
Yersinia

27

Transfusion transmitted infections: Prions

CJD (4 documented cases)

28

Prevention of Infections:

1. Donor Selection – volunteer vs. paid
2. Testing of blood
3. Pathogen inactivation –
4. Avoiding transfusion

See pg27 for effectiveness of testing for infections

29

Immunological reactions: Red cells

Blood Groups: (polymorphic proteins)
• Immediate haemolysis
• Delayed Haemolysis
• Haemolytic disease of the newborn

30

Immunological reactions: Platelets

Post transfusion purpura
HPA – human platelet antigens

31

Immunological reactions: Lymphocytes/HLA (neutrophil antigens)

Graft versus host disease

32

Immunological reactions: Plasma Proteins

Allergy/Anaphylaxis
Donor exposure – drugs/food

33

Blood Groups: Inheritance


Inherited variation of red cell membrane proteins
• ABO system
• Rh system (DCE)
• MNS, K, Fy, Jk, Le, Lu

34

Blood Groups: Antibody reactions

Can be formed against transfused antigens

35

Blood Groups: Antibodies can cause haemolysis

• Of the transfused blood
• Of the recipient blood
• In the fetus/newborn (Haemolytic Disease of the Newborn

36

Blood Groups:The incompatible transfusion: Major Compatibility

• Recipient has antibodies against transfused blood
• E.g. group A blood given to group O patient

37

Blood Groups: The incompatible transfusion: Minor Compatibility

• Transfused blood contains antibodies against recipient cells
• E.g. group O blood transfused to group A patient

38

Most common blood groups

O then A

39

Rare blood groups

AB

40

The basis of the ABO blood group system: explanation

• Virtually all humans express the H antigen on the surfaces of their red cells. This is therefore not antigenic = Group O
• A transferase (alpha – 3-N-acetyl-D galactosaminyltransferase) converts H to A (A and H expressed)
• B transferase (alpha – 3-N-acetyl-D galactosyltransferase) converts the H antigen into the B antigen (B and h expressed).

41

Importance of the ABO system:

• Humans form antibodies against the ABO antigens they lack
• Naturally occurring antibodies
• Stimulated by micro-organisms expressing glycoproteins similar to the ABO antigens
• Usually present by 4 months of age
• Antibodies can cause immediate haemolysis

42

Universal donor

O

43

Universal donor for plasma

AB

44

Positive negativity refers to

RhD

45

White cells: Graft versus host disease (TA-GVHD)

• Donor T cells react against the recipient
• Immunodeficient recipient or of close HLA type to the donor
• Fever, skin rash, hepatitis, diarrhoea, pancytopenia
• Usually fatal but preventable

46

White cells: Graft versus host disease (TA-GVHD)
Prevention

Gamma irradiation of cellular blood components for susceptible recipients

47

Immunological reactions: platelets post transfusion purpura

Systems of human platelet antigens (HPa)
Anti HPA antibodies detectable in the patient’s serum.
Purpura, bleeding and thrombocytopenia
5-12 days after transfusion

48

Immunological reactions: platelets post transfusion purpura treatment

High-dose ivlg 0.4g/kg for 5 days

49

Reactions against plasma proteins (common)

Allergic reactions
• Analphylaxis
• Rash
Febrile reactions

50

Iron overload 1 unit red cells contains

Iron overload 1 unit red cells contains

51

250mg iron

3mg/day

52

Cause of iron overload

Regular transfusion (several years)

53

Toxicity of iron overload

Heart
Liver
Pancreas
Joints
Pituitary

54

Treatment of iron overload

Minimise transfusion
Long term iron chelation (desferrioxamine [s/c] or deferasirox/deferiprone [oral])

55

Transfusion associated circulatory overload: Epi



• Greatest cause of transfusion in UK
• Occurs late in infusion, uncommon in clinical areas experienced in blood transfusion
• Early signs can be detected (raised pulse and BP at 15 mins)

56

Transfusion associated circulatory overload: Treatment

• Slow down the infusion and give frusemide

57

Transfusion associated circulatory overload: Prevention

• Identify at risk patients.
• Give frusemide with transfusion
• 1 unit at a time.

58

The transfusion process

• ABO Grouping
• Antibody screen
• Cross-match (mix donor cells + recipient serum)
• Cross check with previous records (send second sample if no previous sample)

59

Causes of ABO incompatibility:

• Almost always due to patient receiving blood meant for another recipient
• Almost always preventable
• Most common errors:
o Failure to check patient identity at the bedside against the unit to be transfused
o Labelling sample tube away from the patient
o Sample transposition in laboratory

60

When to transfuse red cells


• Acute blood loss >30% of blood volume
• Symptomatic anaemi (usually <7g/dl)
• It is better to treat the cause of the anaemia than to transfuse in most circumstances
• Investigate cause of anaemia before transfusion
• It may be dangerous to transfuse patients with B12 or folate deficiency, a paraprotein or sickle cell disease without consulting a haematologist

61

When to prescribe platelets

• Ensure the reason for low platelets is known
• Bone marrow failure in a well patient if plt <100x109/l

62

When NOT to prescribe platelets

• Consumption of platelets (e.g. ITP, drug induced) unless major bleeding.
• TTP (Thrombocytopenic thrombotic purpura)
• Irreversible marrow failure (e.g. aplastic anaemia) – only transfuse if bleeding.

63

Indications for FFP

For clotting factor replacement:
• Coagulation factor deficiencies when specific factor concentrates are not available
• Multiple coagulation factor deficiencies
→Liver disease
→ Diseminated intravascular coagulation
→ Massive transfusion

• Warfarin reversal with severe bleeding (PC concentrate is preferred choice)

64

Indications for cryoprecipitate

• Fibrinogen supplementation
• If there is bleeding and a fibrinogen level <1.5 g/l
• E.g. DIC advanced liver disease, massive blood transfusion, obstetric bleeding and reversal of fibrinolytic therapy

65

Alternatives to Transfusion:

1. Avoid anaemia/blood loss
a. Reducing blood sampling
b. Preoperative optimisation
c. Tranexamic acid
2. Treat anaemia
a. Identify cause and treat
b. IV iron, erythropoietin
3. Intraoperative cell salvage
4. Artificial blood substitutes?

66

Special Requirements:

Irradiated blood:
• To prevent
• Used for
CNV negative blood

67

Irradiated blood:
• To prevent
• Used for

Prevents GvHD
• Haematology patients (specific conditions and treatments)
• Congenital T cell immunodeficiency
• Intrauterine transfusion/neonatal exchange transfusion
• (Transfusion of blood from a relative)

68

CNV negative blood

Unit does not have anti-CMV antibodies
Neonates under 28 days post term
Elective transfusion in pregnancy (not needed for obstetric haemorrhage)

69

Acute complications:

1. Acute transfusion reaction →
a. Acute haemolysis
b. Bacterial contamination
2. Acute breathlessness
a. Fluid overload
b. Anaphylaxis
c. Transfusion related head injury
3. Minor reactions
a. Rash
b. Febrile reaction

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