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Clinical Pathology > Theme 7 Haemotology: Blood transfusions > Flashcards

Theme 7 Haemotology: Blood transfusions Flashcards

1
Q

Name all the blood components available for transfusion?

A
  1. Red blood cells
  2. Platelets
  3. Plasma
    - fresh frozen plasma
    - cryoprecipitate
    - fractionation (factor concentrates, albumin, immunoglobulin)
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2
Q

Explain the process of filtering blood after it is taken and before it is donated

A
  1. Leucodepletion –> removal of WBCs from the blood thats being donated as they can carry infection and lead to transfusion reaction
  2. Blood is separated into its constituent parts –> RBCs, platelets and plasma
  3. Plasma can either be frozen or cryoprecipitated
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3
Q

What is cryoprecipited?

A

plasma is frozen and then defrosted at 4 degrees

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4
Q

What is the most commonly transfused blood product?

A

1 unit of RBC

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5
Q

1 unit of RBC has a haematocrit of what %?

A

60%

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6
Q

What is haematocrit?

A

the ratio of the volume of red blood cells to the total volume of blood

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7
Q

How are red blood cells for transfusion kept healthy during storage?

A

plasma is replaced by a solution of electrolytes, glycose and adenine to keep the red cells healthy

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8
Q

1 unit transfusion is expected to raise Hb by how much?

A

10g/L

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9
Q

What is:

  1. the Therapeutic dose of 1 unit of RBC
  2. Usual transfusion time
A
  1. 10-20 ml/kg

2. 1.3-3hrs

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10
Q

What 4 situations do NICE Guidance state transfusion is suitable?

A
  1. Bleeding
  2. Anaemia with severe symptoms
  3. Acute anaemia with mild symptoms
  4. Chronic anaemia with symptoms
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11
Q

For platelet transfusion, what is?:

  1. Adult therapeutic dose
  2. Platelet count per dose
  3. Shelf life
  4. Usual transfusion time
A
  1. 4-6 donations
  2. 3x10^11
  3. 5 days
  4. 20-30 mins/unit
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12
Q

How many units of platelets are produced from a unit of whole blood, and how many of these units are pooled together in a pack?

A
  • 1 unit is produced from a unit of whole blood

- 4-6 of these units are pooled together in a single pack

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13
Q

What are apheresis platelets?

A
  • platelets are removed through an apheresis machine that collects platelets and return all other blood constituents to the donor
  • selectively removes platelets
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14
Q

Why do we transfuse platelets?

A

-to treat OR prevent bleeding due to severe thrombocytopenia or platelet dysfunction

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15
Q

What is thrombocytopenia?

A

low platelets

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16
Q

In what conditions should you not give platelets?

A
  • immune thrombocytopenic purpura
  • thrombotic thrombocytopenic purpura
  • heparin induced thrombocytopenia
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17
Q

What does fresh frozen plasma (FFP) contain?

A

all clotting factors

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18
Q

For FFP, what is:

  1. Volume of 1 unit
  2. Usual tranfusion time
  3. Therapeutic dose
A
  1. 300ml
  2. 30 mins/unit
  3. 12-15 mL/kg
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19
Q

Why would we transfuse FFP?

A
  • to replace clotting factors in patients with multiple factor deficiencies
    2. to treat bleeding in patients with abnormal clotting
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20
Q

When should we NOT transfuse FFP?

A
  • to treat single factor deficiencies where a factor concentrate is available e.g haemophilia A when you’re deficient in factor 8 we can just give factor 8
  • to correct abnormal clotting in patients that are not bleeding or having procedures
  • to reduce warfarin
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21
Q

How does warfarin work?

A

it inhibits clotting factors II, VII, IX and X so patients on warfarin are deficient in these clotting factors

22
Q

What is best to reverse warfarin? (much better than FFP)

A

prothrombin complex concentrate

23
Q

What is cryoprecipitate and what does it contain?

A
  • FFP defrosted at 4 degrees and the liquid that melts off is the cryopreciptate
  • contains fibrinogen, von willebrand, factor VIII and factor XIII
24
Q

For cryoprecipitate, what is:

  1. Therapeutic dose
  2. Storage
  3. Shelf life
  4. Volume per unit
  5. Max transfusion time
A
  1. 10-15ml/kg
  2. -30 degrees
  3. 3 years
  4. 15ml
  5. STAT
25
Q

What is cryoprecipitate mainly used for?

A

as a concentrated source of fibrinogen in acquired coagulopathies i.e massive haemorrhage, DIC, liver failure –> ONLY if the patient is bleeding

26
Q

What are the 4 non-immunological complications of tranfusion?

A
  1. Transfusion transmitted infections (TTI)
  2. Transfusion Associated Circulatory Overload (TACO)
  3. Febrile non-haemolytic transfusion reaction (FNHTR)
  4. Iron overload
27
Q

Which infections is every blood donation now tested for?

A

HIV, HBV, HCV, HTLV and syphillis

28
Q

Why does FNHTR occur?

A

FNHTR are due to cytokines or other biologically active molecules that accumulate during storage of blood components

29
Q

What are the signs and symptoms of TTI?

A
  • Rigors
  • high fever
  • severe chills
  • hypotension
  • nausea
  • vomiting
  • dyspnoea
  • circulatory collapse
30
Q

What are the clinical features and treatment of FNHTR?

A

Clinical features:

  • rise of temperature > 1 degree from baseline
  • rigors
  • tachycardia

Treatment:
-is mild so paracetmol

31
Q

What are the signs and symptoms of TACO?

A
  • dyspnoea
  • orthopnoea
  • tachycardia
  • hypertension
  • hypoxemia
  • raised BP
  • elevated jugular venous pulse
32
Q

What are the risk factors for TACO?

A
  • elderly patients
  • small children
  • LVF, renal impairment, low albumin, fluid overload
  • large transfusion volume
  • increased rate of transfusion
33
Q

How do we treat TACO?

A

O2, diuretics, monitor fluid balance

34
Q

What is ABO incompatibility?

A

when a mother’s blood type is O, and her baby’s blood type is A or B. The mother’s immune system may react and make antibodies against her baby’s red blood cells.

35
Q

What are the 6 immunological complications?

A
  1. Acute haemolytic transfusion due to incompability
  2. Delayed haemolytic reaction
  3. Post transfusion purpura
  4. Allergic / anaphylactic reaction
  5. TRALI (transfusion related acute lung injury)
  6. TA-GvHD (transfusion associated graft-versus-host disease)
36
Q

What is acute haemolytic reaction?

A
  • due to transfusion of RBC to a recipient that has pre formed antibodies against antigens that are expressed on the transfused RBC
  • usually due to the patient being given the wrong blood group
  • most often ABO incompatibility
37
Q

What are the signs and symptoms of acute haemolytic reaction due to incompatibility?

A
  • fever and chills
  • back pain
  • infusion pain
  • hypotension
  • haemoglobinuria
  • increased bleeding (DIC)
  • chest pain
  • sense of “impending death”
38
Q

What is cross matching?

A

patients plasma is mixed with donor red cells to see if a reaction occurs

If there is a reaction, RBC units are incompatible and there is a risk of acute haemolysis

If there is no reaction, RBC units are compatible and there is no risk of acute haemolysis

39
Q

How do we try to prevent acute haemolytic reaction?

A

“Group+screen”:

  1. Pre-transfusion testing on patients
    - determination of ABO of Rh (D) group
    - test patient’s plasma for antibodies
    - if positive: antibody identification
    - if negative: no further testing
40
Q

Which test do we use for RBC transfusions?

A

Compatibility testing “cross matching”:

-donor red cells of the correct ABO and Rh group are selected

41
Q

What is cross matching?

A

patients plasma is mixed with donor red cells to see if a reaction occurs

If there is a reaction, RBC units are incompatible and there is a risk of acute haemolysis

If there is no reaction, RBC units are compatible and there is no risk of acute haemolysis

42
Q

What is DAT

A

Direct anti-globulin test to detect antibodies bound on RBC
agglutination = positive reaction
no agglutination = negative reaction

43
Q

when is the onset of the delayed haemolytic reaction?

A

3-14 days following a transfusion of RBC

44
Q

What are the clinical features of delayed haemolytic reaction?

A

fatigue
jaundice
and / or fever

45
Q

Why do allergic reactions in transfused patients occur?

A

due to hypersensitivity of recipient of transfused “random” proteins

46
Q

What are the clinical features of allergic reactions due to transfusion

A
  • rash
  • urticaria
  • pruritus
  • wheeze
  • +- rigors / fevers
47
Q

What is the treatment of allergic reactions?

A

antihistamines, steroids

48
Q

Which patients are at higher risk of a transfusion associated anaphylactic reaction?

A

patients with IgA deficiency and anti-IgA antibodies

49
Q

What is TRALI?

A
  • Transfusion related acute lung injury
  • antibody in blood product attacks the WBCs of the patient
  • the WBC becomes activated and lodge in the pulmonary blood vessels and cause inflammation in the lungs
  • serious complication of transfusion
50
Q

How can you distinguish between TACO and TRALI?

A
  • High BP in TACO
  • Low BP in TRALI
  • TACO gets better with diuretics because its a fluid overload
  • TRALI will be worse with diuretics
51
Q

How long until the onset of “acute lung injury” in TRALI?

A

occuring within 6 hours of a transfusion

52
Q

What are the symptoms of TRALI?

A

low BP, fever, neutropenia

Clinical Pathology (57 decks)

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