Blood transfusions

Question 1

Why should prescribing blood products be taken seriously?

Answer 1

• Transfusion reactions are common even with cross-matched blood
• Blood products are scarce so should be used only when necessary
• Blood group incompatibility is life-threatening complication

Question 2

What are the NICE guidelines recommendation for haemoglobin concentration for those who need RBC transfusion and the concentration target after tranfusion?

Answer 2

• Restrictive Hb concentration for those who need RBC transfusion
  
  • 70g/L
• Hb concentration target after transfusion
  
  • 70-90g/L

Question 3

What are the important blood groups to consider when prescribing blood products and cross-matching?

Answer 3

• ABO blood system
• Group D of rhesus system

Question 4

What are the Rhesus D (RhD) classifications in patients

Answer 4

• RhD+ or RhD-
• Depends on presence of rhesus D surface antigens
• RhD+ (85%): RhD antigens present
• RhD- (15%): RhD antigens absent

Question 5

What happens if a RhD- patient is given RhD+ blood?

Answer 5

• RhD- patient will begin to produce RhD antibodies
• Will not matter for the patient
  
  • Cannot go onto attack their own RBCs because they do not have RhD present on the RBC membrane

Question 6

What happens if a RhD- patient becomes pregnant with a RhD+ fetus (RhD+ partner)?

Answer 6

• Causes Haemolytic Disease of the Newborn (HDN)
• Feotal blood is RhD+ => mother creates RhD antibodies
• Second pregnancy with RhD+ child
• Anti-D antibodies cross placenta and enter foetal circulation and bind to RhD antigens on the feotal RBC surface membranes
• Fotal immune system attacks its own RBCs leading to foetal anaemia

Question 7

What type of RhD blood is given to men and women?

Answer 7

• Women
  
  • Given RhD specific blood to avoid HDN
• Men
  
  • Preferable to give cross-matched blood
  • Possible to give RhD+ blood to a RhD- male in emergency setting

Question 8

Describe the ABO blood group?

Answer 8

• Refers to the presence of A / B antigens on the surface of RBCs
• People produce antibodies to bind to the surface antigen (A or B) that are NOT present on your own RBC membrane
• Important consdieration for O- and AB+ blood

Question 9

Describe the considerations for O- blood?

Answer 9

• Universal donor
• Blood can be given to anyone because there are no AB or Rhesus antigens on donor RBC surface membrane
• They are unlikely to reject this blood as there are no ABO of Rh antigens to attack

Question 10

Describe the considerations for AB+ blood?

Answer 10

• Universal acceptor
• They can receive any donor blood as they do not have any A, B or rhesus antibodies in their circulation so cannot mount an immune response to donor blood

Question 11

Table of the different blood types and their antigens

Answer 11

Question 12

• Blood group A
  
  • What antibodies do they have in plasma?
  • What antigens do they have in RBCs?
  • What blood types are compatible in an emergency?

Answer 12

• Anti-B
• A antigen
• Groups A and O

Question 13

• Blood group B
  
  • What antibodies do they have in plasma?
  • What antigens do they have in RBCs?
  • What blood types are compatible in an emergency?

Answer 13

• Anti-A
• B antigen
• Groups B and O

Question 14

• Blood group AB
  
  • What antibodies do they have in plasma?
  • What antigens do they have in RBCs?
  • What blood types are compatible in an emergency?

Answer 14

• None
• A and B antigens
• Universal recipient

Question 15

• Blood group O
  
  • What antibodies do they have in plasma?
  • What antigens do they have in RBCs?
  • What blood types are compatible in an emergency?

Answer 15

• Anti-A and anti-B
• No antigens
• Can only receive group O

Question 16

What are the two blood tests that should be preformed prior to blood transfusion?

Answer 16

• Group and save (GC&S)
• Crossmatch

Question 17

Describe GC&S?

Answer 17

• Determines patient’s blood group and screens for atypical antibodies
• GC&S is recommended if blood loss is not anticipated but blood may be required if there is greater loss than expected

Question 18

Describe the crossmatch blood test?

Answer 18

• Involves mixing patient’s blood with donor blood to see if an immune reaction takes place
• G&S should be done first
• Recommended if blood loss is anticipated

Question 19

Describe the process of requesting blood products?

Answer 19

• 3 points of identification (name, DOB, CHI no)
• Consent patient
• Label bottles at the bedside
• Complete transfusion request form at the bedside

Question 20

Describe CMV negative blood products?

Answer 20

• CMV is common congenital infection
  
  • Can cause sensorineural deafness and cerebral palsy
• => CMV negative blood should be given to women during pregnancy, intra-uterine transfusions and neonates

Question 21

Why are blood products irradiated?

Answer 21

To reduce graft-versus-host disease in at risk populations

Question 22

Name some patient groups who should receive irradiated blood products?

Answer 22

• Receiving blood from first or second degree family members
• Patients with Hodgkin’s lymphoma
• Recent haematipoietic stem cell transplants
• People receiving purine analogues as chemotherapy

Question 23

Describe the administration of blood products?

Answer 23

• If receiving more than one unit, they should be prescribed individually
• Important observational timings:
  
  • Before transfusion
  • 20 minutes
  • 1 hour
  • At completion
• Admimnstered via green or grey cannula

Question 24

Why should blood be given via large cannulas?

Answer 24

Otherwise the cells will haemolyse due to sheering forces in a narrow tube

Question 25

What are the different parts that a donor's blood is separated into?

Answer 25

* Packed red cells * Platelets * Fresh frozen plasma (FFP) * Cryoprecipitate

Question 26

How are blood products administered?

Answer 26

* Via blood giving set * Has a filter in the chamber which a normal fluid giving set lacks

Question 27

Major constituents of packed red cells?

Answer 27

Red blood cells

Question 28

Indications for packed red cells?

Answer 28

* Acute blood loss * Chronic anaemia where Hb \<70g/L or \<100 in CVD * Symptomatic anaemia

Question 29

Duration of packed red cells administration?

Answer 29

* 2-4 hours * Must be completed within 4 hours of removal from the store

Question 30

Considerations for giving packed red cells?

Answer 30

* 1 unit of blood should increase Hb by 10g/L * Patient RBCs may produce autoantibodies to donor surface antigens * New G&S should be sent before starting another transfusion

Question 31

Indication for giving platelets?

Answer 31

* Haemorrhagic shock in trauma patient * Profound thrombocytopenia (\<20 x10⁹/L) * Normal 150-400) * Bleeding with thrombocytopenia

Question 32

Duration for the administration of platelets?

Answer 32

30 minutes

Question 33

Describe an adult therpeutic dose of platelets?

Answer 33

Should increase platelet levels by 20-40 x10⁹/L

Question 34

Constituents of FFP?

Answer 34

Clotting factors

Question 35

Indications for FFP?

Answer 35

* Disseminated intravascular coagulation (DIC) * Haemorrhage secondary to liver disease * All massive haemorrhages * (given after 2nd unit of packed red cells)

Question 36

Duration of administration of FFP?

Answer 36

30 minutes

Question 37

Major constituents of cryoprecipitate?

Answer 37

* Fibrinogen * Von-Willebrands factor (vWF) * Factor VII * Fibronectin

Question 38

Indications for cryoprecipitate?

Answer 38

* DIC with fibrinogen \<1g/L * Von willebrands disease * Massive haemorrhage

Question 39

Duration of administration of cryoprecipitate?

Answer 39

Stat

Question 40

General complications of red cell transfusions?

Answer 40

* Clotting abnormalities * Electrolyte abnormalities * Hypothermia

Question 41

Describe the clotting abnormalities caused by packed red cell transfusions?

Answer 41

* Due to a dilution effect * The packed red cells do not contamin platelets or clotting factors * To reduce the risk of impairment, FFP, platelets should be administered concurrently in patients receiving more than 4 units of RBCs

Question 42

Describe the electrolyte abnormalities caused by packed red cell transfusions?

Answer 42

* Hypocalcaemia * chelation of calcium by calcium binding agent in preservative * results in reduced serum calcium level * Hyperkalaemia * due to partial haemolysis of RBCs and resultant intracellular potassium release

Question 43

Describe the hypothermia caused by packed red cell transfusions?

Answer 43

* Blood products are thawed from frozen then kept and cool temperatures * They may not be at body temperature at the time of transfusion

Question 44

Name the ACUTE complications from transfusions?

Answer 44

* Anaphylaxis * Acute haemolytic reaction * Transfusion associated circulatory overload * Transfusion related acute lung injury (TRALI) * Form of ARDs, non-cardiogenic pulmonary oedema

Question 45

Name the DELAYED complications from transfusions?

Answer 45

* Infection * Risk of HBV, HCV, HIV, syphilis, malaria * Less concern now blood donors are screened * Graft vs Host Disease (GvHD) * Fever, skin involvement, diarrhoea, vomiting * Iron overload * Patients receiving multiple transfusions (thalassemia)