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? (3)
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 IV 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
How can we manage an anaphylactic transfusion reaction? (4)
- stop transfusion
- IM adrenaline
- ABC support - oxygen, fluids, antihistamine, bronchodilators, corticosteroids
- glucagon if patient takes beta-blockers (may be resistant to adrenaline - refractory bradycardia and hypotension)
What is a non-haemolytic febrile transfusion reaction?
Immune-mediated –> often the result of sensitisation by previous pregnancies or transfusions
Antibodies reacting with WBC fragments in blood product (HLA antibodies) and cytokines that have leaked from blood cell during storage
What are the clinical features of non-haemolytic febrile transfusion reactions? (3)
- fevers
- chills
- otherwise systemically well
How do we manage non-haemolytic febrile transfusion reactions? (3)
- slow / stop transfusion
- antipyretic - IV/PO paracetamol
- if paracetamol reduces temperature appropriately, it is safe to restart transfusion at slower rate and increase subsequent frequency of observations
- monitor
What is TRALI (transfusion-related acute lung injury)?
Non-cardiogenic pulmonary oedema secondary to increased vascular permeability caused by host neutrophils that become activated by substances in donated blood
Granulocyte activation in pulmonary vasculature –> increased vascular permeability
