Blood grouping + transfusions

Question 1

Explain the ABO blood types.

Answer 1

• RBCs can display either antigen A or antigen B on their surface
• Antibodies will be found in the plasma for the antigen that is NOT on the RBC surface (i.e. antigen A present, therefore antibody B in blood)
• If both are present on RBCs, no antibodies in the plasma
• If no antigens are present on RBCs, both antibodies in plasma

Question 2

What is the universal recipient and universal donor?

Answer 2

• Recipient: AB+
• Donor: O

Question 3

What is Rhesus factor?

Answer 3

• Can be either Rh positive or negative
• Rh is a protein found on red cells (most commonly we refer to protein D
• Antibody for Rh is a form of IgG

Question 4

What is haemolytic disease of a foetus and newborn?

Answer 4

• Two forms:
  
  • ABO incompatibility:
    
    • When mothers are type O and foetus is type A/B
    • 1% of type O mothers have IgG against A and/or B
    • These IgG cross the placenta and cause haemolysis
  • Rh incompatibility:
    
    • Rh-D negative mother + Rh-D positive foetus
    • Mother will form IgG anti-D which can cross the placenta
    • Will not affect first born child, but all subsequent Rh-D positive children

Question 5

How does haemolytic disease of foetus and newborn present?

Answer 5

• Jaundice (due to haemolysis)
• Kernicterus (type of brain damage; can cause athetoid cerebral palsy and hearing loss)

Question 6

How do we prevent haemolytic disease of foetus and newborns?

Answer 6

• By giving all mothers unsensitised anti-D Ig - this will remove all foetal RBCs from maternal circulation
• Also use Rh-D negative blood products in women of child-bearing age

Question 7

What is transfusion associated graft-versus-host disease (TA-GVHD)?

Answer 7

• Due to a reaction between transufed blood and the host
• All blood products are irradiated in Australia to prevent this
• Presentation:
  
  • Present 2 weeks after transfusion
  • Rash
  • Pancytopenia
  • Abnormal liver function
• Immunosuppressed people are vulnerable

Question 8

What do you do if there is a transfusion complication?

Answer 8

1. Stop transfusion immediately
2. Evaluate, leave IV, run saline
3. Check for clerical error
4. Complete reaction form
5. Get help from registrar

Question 9

What reactions can arise from a transfusion complication?

Answer 9

• Acute haemolytic transfusion reactions
• Delayed haemolytic transfusion reactions
• Transfusion related acute lung injury
• Bacterial contamination

Question 10

Explain acute haemolytic transfusion reactions

Answer 10

• Usually due to ABO incompatibilities
• Intravascular haemolysis occurs
• Sx:
  
  • <24 hours after transfusion
  • Fever, chill
  • Hypotension
  • Dyspnoea
  • Back pain
  • Haemoglobin
  • Haemoglobinuria
• Complications:
  
  • DIC
  • ARF
  • Mortality (40%)

Question 11

Explain delayed haemolytic transfusion reactions

Answer 11

• Extravascular haemolysis occurs
  
  • RBC antibody formed after transfusion
  • Incomplete compliment activation and RBCs are lysed
• Presents 5-21 days after transfusion:
  
  • Fever, chills
  • Malaise
  • Jaundice
  • Back pain

Question 12

What is transfusion related acute lung injury?

Answer 12

• When HLA class I or II antibodies in donor react with recepient’s HLA antigen - causes non-cardiogenic pulmonary oedema
• Presents as respiratory distress

Question 13

Explain bacterial contamination associated with blood transfusions

Answer 13

• Occurs predominantly in platelet transfusion - risk increased due to storage at room temperature
• Sx:
  
  • Occure during the transfusion
  • Severe fever, rigors
  • Hypotension