Transfusion reactions (CH) Flashcards
Why are blood transfusions usually safe? (2)
- due to extensive screening
- pre-transfusion testing
What are the thresholds for blood transfusions in patients with vs without ACS?
Non-urgently these are transfused over 90-120 minutes:
- with ACS = 80g/L
- without ACS = 70g/L
What are adverse events in blood transfusions mediated by?
Interaction of recipient antibodies to foreign antigens contained in blood product
How can immune-mediated transfusion reactions be classified?
- acute - occur within 24h of transfusion
- delayed - occurs days to weeks after transfusion
What are some examples of acute transfusion reactions? (4)
- acute haemolytic
- allergic/anaphylaxis
- febrile non-haemolytic
- TRALI: transfusion-related acute lung injury
What are acute transfusion reactions usually due to?
Clerical error - identification is critical because of the high probability of a second patient receiving the wrong blood product at the same time
What are some examples of delayed transfusion reactions?
- delayed haemolytic transfusion reactions
- GvHD
- post-transfusion purpura
What are some non-immune-mediated transfusion reactions? (4)
- TACO: transfusion-associated circulatory overload
- infective reaction
- transfusion-associated sepsis
- haemolysis
What is an acute haemolytic transfusion reaction?
Result of ABO-RBC incompatibility –> leads to RBC (transfused) destruction by IgM antibodies
What are the clinical features of acute haemolytic transfusion reaction? (8)
- fever + rigors
- tachycardia
- hypotension
- abdominal/chest pain
- dark urine
- headaches
- N&V
- agitation/anxiety (within a few mins)
How can we investigate an acute haemolytic transfusion reaction?
Positive Direct Coomb’s test (antiglobulin test; may be negative if all cells rapidly destroyed)
Haemoglobinuria
Repeat ABO testing
How do we manage an acute haemolytic transfusion reaction? (3)
- stop transfusion
- confirm diagnosis - check ID, cross-match and blood typing, Coomb’s test
- supportive care - fluid resuscitation, urine output goal >100mL (can elicit forced diuresis with flV mannitol)
What are some complications of acute haemolytic transfusion reactions? (3)
- DIC
- renal failure
- severe hypotension
What is an allergic/anaphylactic transfusion reaction?
Hypersensitivity reactions to allergens in the transfused component
In which patients is an anaphylaxis transfusion reaction common in?
IgA deficiency patients who have anti-IgA antibodies
More common with plasma-rich blood products e.g. FFP, cryoprecipitate and platelets
What are the clinical features of a minor allergic transfusion reaction?
Pruritus and urticaria
(Urticaria without anaphylaxis)
What are the clinical features of allergic/anaphylactic transfusion reactions? (5)
- hypotension
- dyspnoea
- wheezing
- angioedema
- stridor
How can we investigate anaphylactic transfusion reaction?
Serum IgA & IgA antibody screen
How can we manage a minor allergic transfusion reaction? (3)
- temporarily stop/slow transfusion
- antihistamine (chlorphenamine)
- monitor