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Haematology > Blood transfusion > Flashcards

Blood transfusion Flashcards

1
Q

Why do we transfuse blood?

A
  • For replacement of blood loss
  • Failure of blood production
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2
Q

What differentiates the blood groups?

A
  • Arrise from antigens
    • (something that invokes immune response
  • Red cell antigens are expressed on the cell surface
  • Can provoke antibodies
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3
Q

How can we imagine ABO blood types?

A

Donuts and Sprinkles

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4
Q

What does ABO gene encode for?

A

Glycosyltransferase

These establish linkages: Glycans added to proteins or lipids on Red Cells

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5
Q

What do A and B genes code for?

A

Code for transferase enzymes:

  • A antigen is N-acetyl-galactosamine
  • B antigen is galactose
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6
Q

What does O code for?

A
  • ‘O’ gene is non-functional allele
  • So A and B are (co-)dominant and O is recessive
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7
Q

Which blood groups have antibodies against each other?

A
  • If blood group A, have antibodies against B
  • If blood group B, have antibodies against A
  • If blood group O, have antibodies against A and B
  • If blood group AB, have no antibodies against A and B
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8
Q

What does IgM do?

A
  • anti-A/B naturally occurring
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9
Q

Percentage of different blood groups?

A
  • A 42%
  • B 9%
  • AB 3%
  • O 46%
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10
Q

Which red cell vs FFP (fresh frozen plasma) blood groups can be administered to others?

A

Please see table:

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11
Q

What is RhD?

A

Either Rhesus negative or positive

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12
Q

What is notable about anti-RhD?

A
  • RhD negative individuals can make anti-D if exposed to RhD+ cells
    • Transfusion or pregnancy
  • Anti-D can cause transfusion reactions or haemolytic disease of the newborn
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13
Q

What do we cover for blood donors?

A
  • Extensive ‘behavioural’ screening
  • Sex, age, travel, tattoos…………
  • Tested for ABO and Rh blood groups
  • Screened for HepB/C/E, HIV, syphilis
  • Variably screened for:
    • HTLV1, malaria, West Nile virus, Zika virus…
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14
Q

What are the components of blood?

A
  1. Plasma (clotting, coagulation factors, albumin, antibodies)
  2. Buffy coat (Platelets, white cells)
  3. RBCs
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15
Q

What are 4 common indications for red cell transfusion?

A
  1. To correct severe acute anaemia, which might otherwise cause organ damage
  2. To improve quality of life in patient with otherwise uncorrectable anaemia
  3. To prepare a patient for surgery or speed up recovery
  4. To reverse damage caused by patient’s own red cells - Sickle Cell Disease
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16
Q

RBC

How do we store?

How long do we transfuse over?

Increments?

A
  • Stored at 4 degrees
  • Transfuse over 2-4hrs
  • 1 unit increments ~5 g/L
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17
Q

Platelets
Store?

Increments?

Transfuse over?

A
  • Stored at 22 degrees, shelf life of 7 days
  • 1 dose platelets (=4 pooled or 1 apheresis donor)
    • increments 20-40.109/L
  • 20-30mins transfusion
18
Q

Platelets: What do we do for….?

Massive haemorrhage

Bone marrow failure

Surgery prophylaxis

Cardiopulmonary bypass

A
  • Massive haemorrhage
    • Keep platelet count above 75x109/l
  • Bone marrow failure
    • platelet count <10-15 × 109/litre
    • or <20 × 109/litre if additional risk, e.g. sepsis
  • Prophylaxis for surgery
    • Minor procedures 50x109/l;
    • More major surgery 80x109/l; CNS or eye surgery 100x109/l
  • Cardiopulmonary bypass
    • use only if bleeding
19
Q

Fresh Frozen Plasma

How many units from?

How do we store?

Indications for use?

Lab test?

A
  • 1 unit from 1 unit of blood
  • Store frozen, allowing 30 mins to thaw
  • Massive haemorrhage, DIC with bleeding or prophylaxis
  • PT and APTT
20
Q

Cryoprecipitate

How many pools?

Store?

Lab test?

A
  • 1-2 pools if fib <1.0g/dl (1.5g/dl)
  • Frozen, allow 20 mins to thaw
  • Fibrinogen
21
Q

How does practical blood banking actually work?

A
  • Blood sent to Blood Bank
  • ‘Second sample’ now implemented
  • Group and Screen/Save
  • Cross match
    • Tariff defined by ’MSBOS’
  • Samples kept for 7 days
    • But only valid for 2 days if recent transfusion
22
Q

What are the main causes of near miss incidents?

A

98.9% poor practice, shocking

23
Q

What is checked for in “group and screening”?

A
  • ABO and RhD type
  • Checked against historical records
  • Screen for allo-antibodies in serum
24
Q

Please explain Coombs test:

A

(AKA antiglobulin test or AGT) is either of two clinical blood tests used in immunohematologyand immunology.

The two Coombs tests are the direct Coombs test (DCT, aka direct antiglobulin test or DAT), and the indirect Coombs test (aka indirect antiglobulin test or IAT)

25
Q

What does direct Coomb’s test show?

A

Direct:

  • autoimmune haemolytic anaemia
  • passive anti-D
  • haemolytic transfusion reactions

Indirect:

  • Cross matching
26
Q

What are the clinically significant antibodies reactive at 37 degrees?

A

Usually:

  • ABO
  • Rh
  • Kell
  • Duffy
  • S, s, U
  • P
  • Kidd

Sometimes:

  • Cartwright
  • Lutheran
  • Gerbich
  • Lan
  • Dombrock
  • Ata
  • Inb
  • Vel
  • CSa

Never:

  • Bg
  • Ch/Rg
  • Lewis
  • JMH
  • Xga
27
Q

What are the availabilities of red cells?

A
  • Minutes – O RhD Neg red cells (AB plasma)
  • Urgent – Type specific (ABO/ RhD)
  • Non-urgent – Full cross match
    • Select correct ABO/ RhD type
    • if allo-antibodies choose antigen negative blood
28
Q

Massive Haemorrhage

Definitive management?

Immediate supply of?

A
  • Good comms between all teams essential
  • Management:
    • Rapid Control of bleeding
    • Obstetric intervention, surgery, interventional radiology
  • Immediate supply of:
    • 6 units red cells
    • 4 units FFP (cryoprecipitate?)
    • 1 unit platelets
29
Q

What is the major haemorrhage protocol for grampian?

A

See images

30
Q

How should a decision to transfuse be made?

A
  • Should be based on a careful assessment of the patient’s clinical state and must be justified as an essential to prevent major morbidity or mortality
  • Never events: death or harm (transfusion or ABO incompatable)
31
Q

Adverse effects of RBC transfusion contrasted with other risks (USA data).?

A
32
Q

What are important messages surrounding risks of transfusion?

A
  • ABO incompatable transfusions are tip of the iceberg and result from failure to identify patient, bedside checklist is key
  • Pulmonary complications, particularly transfusion associated circulatory overload (TACO) cause the most deaths and morbidity
  • Delayed transfusions are also an important cause of death
  • Over the last 8 years pulmonary complications account for 53.7% of deaths and delays to transfusion 22.8%.
33
Q

What is prion disease?

A
  • Transmittable by blood transfusion from early in disease in sheep
  • 4 possible cases in humans
  • steps taken to reduce risk potential transmission
    • Leucodepletion 1998
    • UK plasma not used for fractionation
    • Imported FFP for all patients born after 1996
  • Are 1:2000 UK population carriers?
34
Q

What is the general management of reactions to transfusion?

A
  • Stop transfusion
  • Check patient identity against component label
  • Consider: anaphylaxis, circulatory overload (TACO), acute haemolytic transfusion reaction (AHTR), bacterial infection, lung injury (TRALI) (other…)
35
Q

Transfusion Reactions: Pyrexia

Possible cause?

Management?

A
  • FNHTR (febrile non-haemolytic transfusion reaction)
  • Anti-pyretic
  • Other symptoms usually more concern (shock / DIC)
36
Q

Transfusion reactions: Urticaria (hives)

Possible cause?

Management?

A
  • Mild allergic reaction, anaphylaxis
  • Antihistamine
  • Other symptoms usually more concern (bronchospasm / shock)
37
Q

Transfusion reactions: Dyspnoea

Possible cause?

Management?

A
  • TACO, TRALI, Anaphylaxis
  • O2
  • diuretic
  • ventilation
  • adrenaline
38
Q

Transfusion reaction: Shock

Possible cause?

Treatment?

A
  • IBCT, Anaphylaxis, TRALI, TAS
  • adrenaline(IV)/Hydrocortisone/Antihistamine
  • IV fluid / ITU admission
  • ventilation
  • antibiotics,
  • FFP/platelets if DIC
39
Q

Please explain the development of maternal Anti D antibodies?

A
  • Mother is rhesus negative
  • Baby is rhesus positive
  • Mother’s blood becomes sensitive to the bambino’s blood!
  • IgG crosses placenta
  • Causes haemolytic problems in the newborn - placenta can also breakaway.
40
Q

Haemolytic disease of newborn?

A
  • Rh D most immunogenic
    • also c, K
    • other Rh antigens, Jka, ABO less immunogenic
    • Positive DAT at birth, anaemia, jaundice
41
Q

Haemolytic disease of newborn (HDN)

How can we use prophylaxis for HDN?

How do we treat HDN?

A
  • Prevention using prophylactic anti-D
    • Sensitising events
    • Routine at 28/40
  • Treatment by careful monitoring
    • Antibody titres
    • Doppler ultrasound
    • Intrauterine transfusions
  • Neonatal alloimmune thrombocytopenia (NAIT) similar process for platelets
42
Q

What cellular therapies are available for HDN?

A
  • Leucapheresis
    • Bone marrow harvests
    • Donor lymphocyte infusions
  • ‘Other banks’
    • Bone, milk, tendons, heart valves, faecal
    • Islet cells, mesenchymal stem cells
  • Gene therapies

Haematology (16 decks)

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