Blood Products Flashcards

1
Q

What are the different blood fractions?

A

1) Packed red cells

2) Platelet rich plasma

3) Platelet concentrate

4) Fresh frozen plasma (FFP)

5) Cryoprecipitate

6) SAG-Mannitol blood

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2
Q

What is a blood product?

A

A blood product is any part of the blood that is collected from a donor for use in a blood transfusion.

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3
Q

What are the two important blood groups?

A

1) ABO blood system

2) group D of the rhesus system

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4
Q

How can a patient’s blood group be classified according to the Rhesus system?

A

RhD+ or Rh-

This refers the presence or absence of Rhesus D surface antigens on the RBCs.

I.e. RhD+ means they have RhD antigens present.

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5
Q

Is being RhD+ or RhD- more common?

A

RhD+ (85%) is more common.

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6
Q

How can RhD be implicated in pregnancy?

A

1) A woman is born with RhD- blood. Her partner is RhD+ and she becomes pregnant with a fetus that is also RhD+.

2) During childbirth, she comes into contact with the foetal (Rh+ve) blood and develops antibodies to it.

3) She later becomes pregnant with a second child that is also Rh +ve.

4) The woman’s anti-D antibodies cross the placenta during this pregnancy and enter the foetal circulation, which contains RhD+ blood, and bind to the foetus’ RhD antigens on its RBC surface membranes.

5) This causes the foetal immune system to attack and destroy its own RBCs, leading to foetal anaemia –> haemolytic disease of the newborn (HDN).

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7
Q

What happens when a RhD- person is given RhD+ blood?

A

A RhD- patient will make RhD antibody (anti-D) if they are given RhD+ blood.

This is not a problem as they cannot then go on to attack their own RBCs as they do not have RhD present on their RBC membrane.

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8
Q

How can haemolytic disease of the newborn be avoided?

A

If the mother is RhD negative, she’ll be offered injections of anti-D immunoglobulin at certain points in her pregnancy when she may be exposed to the baby’s red blood cells.

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9
Q

What does the ABO blood group refer to?

A

The presence of A and / or B antigens on the surface of RBCs.

I.e. RBCs with A antigens will produce anti-B antibodies.

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10
Q

For blood type A, give the:

1) antibodies in plasma
2) antigens on RBC
3) blood types compatible in emergency

A

1) anti-B
2) A antigen
3) A, O

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11
Q

For blood type B, give the:

1) antibodies in plasma
2) antigens on RBC
3) blood types compatible in emergency

A

1) anti-A
2) B antigen
3) B, O

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12
Q

For blood type O, give the:

1) antibodies in plasma
2) antigens on RBC
3) blood types compatible in emergency

A

1) anti-A and anti-B
2) none
3) O

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12
Q

For blood type AB, give the:

1) antibodies in plasma
2) antigens on RBC
3) blood types compatible in emergency

A

1) none
2) A and B antigens
3) A, B, AB, O

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13
Q

Which blood type is the universal donor?

A

O negative: this blood can be given to anybody, irrespective of the recipient’s blood group, because there are no AB or Rhesus antigens on the donor RBC surface membrane.

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14
Q

Which blood type is the universal recipient?

A

AB+ve: you can give this recipient any donor blood, irrespective of the ABO or Rhesus status.

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15
Q

What 2 blood tests are performed prior to blood transfusion?

A

1) Group and save (G&S)

2) Crossmatch (X-match)

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16
Q

What does G&S involve?

A

This determines the patient’s blood group (ABO and RhD) and screens the blood for any atypical antibodies.

The process takes around 40 minutes.

No blood is issued.

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17
Q

When is a G&S recommended?

A

If blood loss is not anticipated, but blood may be required should there be greater blood loss than expected.

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18
Q

What is a X-match involve?

A

Involves physically mixing the patient’s blood with the donor’s blood, in order to see if any immune reaction takes places.

If it does not, the donor blood is issued and can be transfused in to the patient.

This process also takes ~40 minutes, in addition to the 40 minutes required to G&S the blood (which must be done first).

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19
Q

What must be done first, XM or G&S?

A

G&S

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20
Q

When is a XM done?

A

A X-match is done if blood loss is anticipated, but the surgeon will usually inform you of this.

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21
Q

What stages are involved in requesting blood products?

A

1) Using 3 points of patient identification e.g. name, DOB, and patient number.

2) Consent the patient appropriately.

3) Labeling the bottle at the bedside.

4) Completing the transfusion request form at the bedside.

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22
Q

What is cytomegalovirus (CMV)?

A

A common congenital infection that may lead to sensorineural deafness and cerebral palsy.

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23
Q

When is it especially important that CMV negative blood is given?

A

CMV negative blood should be given to:

a) women during pregnancy
b) intra-uterine transfusions
c) neonates (up to 28 days)

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24
Q

What is irridiated blood?

A

Irradiated blood is blood that has been treated with radiation (by x-rays or other forms of radioactivity) to prevent Transfusion- Associated Graft-versus-Host Disease (TA-GvHD).

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25
Q

What disease do irradiated blood products reduce the risk of?

A

graft-versus-host-disease in at risk populations

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26
Q

Which populations should receive irradiated blood?

A

1) Those receiving blood from first or second-degree family members

2) Patients with Hodgkin’s Lymphoma

3) Recent haematpoietic stem cell(HSC) transplants

4) After Anti-Thymocyte Globulin (ATG) or Alemtuzumab therapy

5) Those receiving purine analogues (e.g. fludarabine) as chemotherapy

6) Intra-uterine transfusions

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27
Q

How should blood products be prescribed if a patient requires more than one unit of blood?

A

Each unit must be prescribed individually

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28
Q

Whilst the patient is receiving the blood transfusion, how often should observations be carried out?

A

1) before transfusion starts

2) 15-20 minutes after it has started

3) at 1 hour

4) at completion

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28
Q

What is the major constituent in packed red cells?

A

RBCs

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28
Q

What cannula should be used to administer blood products?

Why?

A

Blood products should only be administered through a green (18G) or grey (16G) cannula.

Otherwise the cells haemolyse due to sheering forces in the narrow tube.

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29
Q

Indications for transfusion of packed red cells?

A

1) acute blood loss

2) chronic anaemia where the Hb ≤70g/L (or ≤100g/L in those with cardiovascular disease)

3) symptomatic anaemia

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30
Q

Over what period should packed red cells be administered?

A

2-4 hours

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31
Q

How soon after coming out of the store should packed red cells be administered?

A

Within 4 hours of coming out of the store.

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31
Q

1 unit of blood should increase a patient’s haemoglobin by how much?

A

Approx 10g/L

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32
Q

How are packed red cells obtained?

A

Obtained by centrifugation of whole blood.

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33
Q

What is the major constituent of fresh frozen plasma (FFP)?

A

Clotting factors (also albumin & immunoglobulin)

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34
Q

Give some indications for FFP

A

1) Disseminated Intravascular Coagulation (DIC)

2) Any haemorrhage secondary to liver disease

3) All massive haemorrhages (commonly given after the 2nd unit of packed red cells)

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35
Q

Over what time period is FFP typically administered?

A

30 mins

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36
Q

What are the major constituents in cryoprecipitate?

A
  • fibrinogen
  • von Willebrands Factor (vWF)
  • factor VIII
  • fibronectin
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37
Q

Indications for cryoprecipitate?

A

1) DIC with fibrinogen <1g/L

2) von Willebrands Disease

3) Massive haemorrhage

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37
Q

What does Factor 5 Leiden involve?

A

This is an inherited disorder of blood clotting that involves a mutation in Factor 5.

This increases the risk of clotting (as it resists degradation by protein C).

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37
Q

What happens in von Willebrand disease?

A

vWf is deficient, predisposing to bleeding.

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37
Q

What is von Willebrand factor?

A

A blood glycoprotein that promotes hemostasis, specifically, platelet adhesion.

37
Q

Duration over which cryoprecipitate is admistered?

A

Stat

38
Q

What is SAG-Mannitol blood?

A

Removal of all plasma from a blood unit and substitution with:
1) Sodium chloride
2) Adenine
3) Anhydrous glucose
4) Mannitol

38
Q

Indication of SAG-Mannitol blood?

A

The product is indicated for use only with apheresis procedures using automated apheresis machines for the preservation of red blood cells.

38
Q

Duration over which platelets are admistered?

A

30 mins

39
Q

Indications for the transfusion of platelets?

A

1) Haemorrhagic shock in a trauma patient

2) Profound thrombocytopenia (<20 x 109/L; normal range 150 – 400)

3) Bleeding with thrombocytopenia

4) Pre-operative platelet level <50 x 109/L

39
Q

1 ATD (adult therapeutic dose) of platelets should increase platelet levels by how much?

A

Approx 20-40 x 10^9/L.

40
Q

Which blood products must be crossmatched?

A

1) packed red cells
2) FFP
3) cryoprecipitate
4) whole blood

40
Q

Which blood product can be ABO incompatible in adults?

A

Platelets

41
Q

What are cell saver devices?

A

These collect patients own blood lost during surgery and then re-infuse it.

42
Q

Who may cell saver devices be useful in?

A

They may be acceptable to Jehovah’s witnesses.

43
Q

In some surgical patients the use of warfarin can pose specific problems and may require the use of specialised blood products.

What are the steps in immediate or urgent surgery in patients taking warfarin?

A

1) stop warfarin

2) vitamin K

3) FFP

4) 4. Human Prothrombin Complex (reversal within 1 hour)

44
Q

What is the 1st line agent for warfarin reversal?

A

Vitamin K

45
Q

What is the threshold for transfusion of red cells in:

a) patients with ACS
b) patients without ACS

A

a) 80 g/L
b) 70 g/L

46
Q

At what temp should RBCs be stored prior to tranfusion?

A

4 degrees

47
Q

In a a non-urgent scenario, how quickly is a a unit of RBC usually transfused?

A

over 90-120 minutes

48
Q

What are irradiated blood products depleted of?

A

T-lymphocytes

49
Q

What blood product can be used for the emergency reversal of anticoagulation in patients with either severe bleeding or a head injury with suspected intracerebral haemorrhage?

A

Prothrombin complex concentrate

50
Q

What are some general complications of packed red cell transfusions?

A

1) Clotting abnormalities

2) Electrolyte abnormalities

3) Hypothermia

51
Q

How does the transfusion volume affect complications?

A

Complications become progressively more likely with increasing transfusion volume.

52
Q

What can cause clotting abnormalities during a transfusion?

A

1) Due to a dilution effect, as the packed red cells transfused do not contain any platelets or clotting factors.

2) Specific conditions like trauma also in themselves can cause coagulopathy.

53
Q

How can the risk of clotting impairment in a packed red cell transfusion be reduced?

A

FFP and platelets should be administered concurrently.

(typically done for patients receiving more than 4 units RBCs)

54
Q

What are the 2 main electrolyte abnormalities that can occur in blood transfusions?

A

1) hypocalcaemia

2) hyperkalaemia

55
Q

How can a blood transfusion cause hypocalcaemia?

A

Chelation of calcium by the calcium binding agent in the preservative results in a reduced serum calcium level.

56
Q

How can a blood transfusion cause hyperkalaemia?

A

Due to the (inevitable) partial haemolysis of the RBCs and the resultant release of intracellular potassium.

57
Q

How can blood transfusions result in hypothermia?

A

As blood products are thawed from frozen and then kept at cool temperatures, they may not be up to body temperature by time of transfusion, especially in a major haemorrhage protocol scenario.

Rapid transfusion of these products can lead to a drop in the patient’s core temperature, hence regular monitoring of core body temperature is always required during a blood product transfusion.

58
Q

What can transfusion specific complications be divided into?

A

Acute & delayed.

59
Q

When do acute transfusion complications typically occur?

A

soon after the transfusion has been started.

60
Q

What are the possible acute transfusion complications?

A

1) acute haemolytic reaction

2) transfusion associated circulatory overload

3) transfusion related acute lung injury (TRALI)

4) others:
- mild allergic reaction
- non haemolytic febrile reactions
- anaphylaxis
- infective/bacterial shock

61
Q

What is an acute haemolytic reaction caused by?

A

ABO incompatibility.

This is caused by transfusion of the INCORRECT blod type, the most common cause being ABO blood group incompatibility.

62
Q

What happens in an acute haemolytic reaction?

A

Donor RBCs are destroyed by the recipient’s preformed Abs, resulting in haemolysis.

63
Q

How may patients with an acute haemolytic reaction present?

A

Early:
- urticaria
- hypotension
- fever
- anxiety
- may have evidence of haemoglobinuria (i.e. red coloured urine) from the rapid haemolysis

Late:
- widespread haemorrhage secondary to DIC

64
Q

What will blood tests should in acute haemolytic reaction?

A
  • reduced Hb
  • low serum haptoglobin
  • high LDH
  • high bilirubin
65
Q

What can confirm the diagnosis of an acute haemolytic reaction?

A

A positive Direct Antiglobulin Test (DAT) will confirm the diagnosis.

66
Q

Who should you inform in an acute haemolytic reaction?

A

Urgently inform blood bank that you suspect this has happened, as they may have dispensed further incorrect blood.

67
Q

Management of acute haemolytic reaction?

A

1) stop transfusion

2) begin supportive measures e.g. fluids & O2

68
Q

What happens in transfusion-associated circulatory overload (TACO)?

A

Excessive rate of tranfusion e.g. in patients with pre-existing HF.

69
Q

Presentation of TACO?

A
  • dyspnoea
  • features of fluid overload e.g. pulmonary oedema
69
Q

Management of TACO?

A

1) slow or stop transfusion

2) consider IV loop diuretics (e.g. furosemide)

3) consider O2

70
Q

What is transfusion related acute lung injury (TRALI)?

A

This is a form of Acute Respiratory Distress Syndrome (ARDS), a non-cardiogenic cause of pulmonary oedema.

71
Q

What happens in TRALI?

A

Non-cardiogenic pulmonary oedema thought to be secondary to increased vascular permeability caused by host neutrophils that become activated by substances in donated blood.

72
Q

Presentation of TRALI?

A
  • hypoxia
  • pulmonary infiltrates on CXR
  • fever
  • hypotension
73
Q

Management of TRALI?

A

1) stop transfusion

2) O2 & supportive care

3) get urgent CXR

These patients have a high mortality.

74
Q

What is a non-haemolytic febrile reaction?

A

An unpleasant, but usually non-life threatening reaction found in 1-2% of patients.

Thought to be caused by antibodies reacting with white cell fragments in the blood product and cytokines that have leaked from the blood cell during storage.

75
Q

Features of a non-haemolytic febrile reaction?

A
  • fever
  • chills
76
Q

Which blood product tranfusion is most likely to cause a non-haemolytic febrile reaction?

A

Platelet transfusion

77
Q

Management of a non-haemolytic febrile reaction?

A

1) slow or stop transfusion

2) antipyretics e.g. paracetamol

3) antihistamines e.g. chlorphenamine

4) monitor

78
Q

What is a minor allergic reaction to a blood transfusion thought to be caused by?

A

Thought to be caused by foreign plasma proteins

79
Q

Presentation of a minor allergic reaction to a blood transfusion?

A

1) pruritus
2) urticaria

80
Q

management of a minor allergic reaction to a blood transfusion?

A

1) temporarily stop transfusion

2) antihistamine e.g. chlorphenamine

3) monitor

81
Q

Presentation of anaphylaxis caused by a blood transfusion?

A

1) hypotension
2) SOB
3) wheezing
4) angioedema

81
Q

What is anaphylaxis caused by a blood transfusion thought to be the result of?

A

Can be caused by patients with IgA deficiency who have anti-IgA antibodies.

82
Q

Management of anaphylaxis caused by a blood transfusion?

A

1) stop transfusion

2) IM adrenaline

3) ABCDE support e.g. O2 & fluids

83
Q

What are 3 delayed transfusion complications?

A

1) infection e.g. Hepatitis B, Hepatitis C, HIV, syphilis, malaria, or vCJD

2) Graft vs. Host Disease (GvHD)

3) iron overload

84
Q

What does GvHD occur due to?

A

GvHD occurs due to an HLA-mismatch between donor and recipient.

85
Q

When is GvHD most common?

A

It is most common in the transfusion of non-irradiated blood products to an immunocompromised recipient.

86
Q

Clinical features of GvHD?

A
  • fever
  • skin involvement (ranging from macropapular rash to toxic epidermal necrolysis)
  • diarrhoea
  • vomiting
87
Q

Who is iron overload a complication of transfusion more common in?

A

Most common in patients that receive repeated transfusions, such as in thalassaemia.

88
Q

Presentation of iron overload as a complication of transfusion?

A

1) cirrhosis
2) onset of diabetes (as a result of pancreas involvement)
3) cardiomegaly & conduction disturbances
4) arthralgia
5) hyperpigmentation

89
Q

Give some examples of operations where there is a DEFINITE chance of transfusion?

A
  • Total gastrectomy
  • Oophorectomy
  • Oesophagectomy
  • Elective AAA repair
  • Cystectomy
  • Hepatectomy
90
Q

What blood product should be ordered prior to surgery in operations where there is a definite chance of transfusion?

A

Cross match 4-6 units depending on local protocols.

91
Q

What blood product should be ordered prior to surgery in operations where there is an unlikely chance of transfusion (e.g. laparoscopic cholecystectomy, appendicectomy)?

A

Group and save

92
Q

What blood product should be ordered prior to surgery in operations where there is a likely chance of transfusion (e.g. salpingectomy for ruptured ectopic pregnancy, total hip replacement)?

A

Cross-match 2 units

93
Q

FFP vs cryoprecipitate?

A

FFP –> made from plasma which is separated from donor blood and frozen to minus 35°Centigrade to preserve it.

Cryoprecipitate –> made from FFP which is frozen and repeatedly thawed in a laboratory to produce a source of concentrated clotting factors including Factor VIII, von Willebrand factor and fibrinogen.

94
Q
A