Canonical Question
Blood – Consequences
Variant family: at least one exam appearance has different scope. The appearance record controls whether this master answer is safe to display on that Past Paper.
Master answer
Adverse Consequences of Blood Transfusion
1. Acute (<24 hours)
1a) Immune-mediated
| Problem | Methods to Minimize | |
|---|---|---|
| Allergic reaction to plasma proteins | mild (urticarial) or severe (anaphylaxis) | Pre-treatment in high risk patients |
| Acute Haemolytic transfusion reaction | incompatibility of donor and recipient blood leads to widespread haemolysis and circulatory collapse | Group and screening |
| Febrile non-haemolytic transfusion reaction (FNHTR) | due to stored cytokines and/or the presence of recipient alloantibodies | Careful monitoring and early cessation of transfusion |
| Transfusion related acute lung injury (TRALI) | noncardiogenic pulmonary oedema caused by HLA antibodies in donor plasma directed against recipient leukocytes or bioactive lipids which accumulate during storage | Careful monitoring and early cessation of transfusion |
1b) Non-immune mediated
| Problem | Methods to Minimize | |
|---|---|---|
| Sepsis | bacterial infections are most common with platelets as they are stored at room temperature | Safe and sterile methods of storage |
| Transfusion Related Circulatory overload (TACO) | fluid overload usually due to rapid or massive transfusion | Careful monitoring and early cessation of transfusion |
| Non-immune mediated haemolysis | Careful monitoring and early cessation of transfusion | |
| Hypothermia | Careful monitoring and early cessation of transfusion | |
| Dilutional coagulopathy | Careful monitoring and early cessation of transfusion |
2. Delayed (>24 hours)
2a) Immune-mediated
| Problem | Methods to Minimize | |
|---|---|---|
| Delayed haemolytic transfusion reaction | Production of anti-donor antibodies post-transfusion May be associated with transfused malaria | Careful monitoring and early cessation of transfusion |
| Transfusion-related immunomodulation (TRIM) | transient immunosuppression in blood recipients which may be due to release of cytokines from donor lymphocytes | Careful monitoring and early cessation of transfusion |
| Alloimmunisation | development of antibodies during exposure to blood products, resulting in an amplified reaction on subsequent exposure Can cause post transfusion thrombocytopenia and purpura | Re-screening every 48-72 hours |
| Transfusion Associated Graft vs. Host Disease | Profound bone marrow aplasia >90% mortality Viable donor T cells implant and attack recipient tissues | Careful monitoring. Re-screening |
2b) Non-immune mediated
| Problem | Methods to Minimize | |
|---|---|---|
| Iron overload | most common in chronically transfused patients | Monitoring of Iron levels |
| Transfusion-related infection | Viral – the risk of HIV, HTLV 1&2 and HCV is <1/1 million. The risk of contracting HBV is slightly higher at 1/500,000. Other – malaria, vCJD, Dengue Fever, West Nile Virus | Pre-screening of donors, screening of collected blood as per local guidelines (different for different areas) |
3. Storage Lesions
A storage lesion refers to the changes that occur to a sample of blood during storage. (Note: Australian Red cross anti-coagulates Whole blood with CPD, but washes and stores Red Cells in SAGM).
| Problem | Methods to Minimize | |
|---|---|---|
| Physical changes | Reduction in the viability of RBCs due to shape changes and reduced deformability Formation of microaggregates | Careful monitoring and usage of products within a specified period |
| Hyperkalaemia | plasma K can be >20 at 28 days in stored blood due to inactivation of the red cell Na/K ATPase pump. | Careful monitoring and usage of products within a specified period |
| High citrate load | can lead to hypocalcaemia and alkalosis (less or nil in SAGM) | Use of SAGM for storage |
| Reduction in 2,3-BPG | causes left shift of the oxygen/haemoglobin dissociation curve (less in CPDA1) | Use of CPDA1 |
| Renal impairment | Due to Increase in free haemoglobin from cell lysis | Routine monitoring of renal function and careful monitoring during transfusion |
Massive Transfusion
- Replacement of >1 blood volume in 24 hours
- 50% of blood volume in 4 hours
Adverse consequences of massive transfusion
| Problem | Methods to Minimize | |
|---|---|---|
| Hypothermia | Cooled products | Appropriately re-warm products. Use of blood warmers |
| Poor O2 delivery | Depletion of 2,3 DPG in PRBC | |
Haemostatic abnormalities | Dilutional coagulopathy | Monitor coagulation profile at appropriate intervals during massive transfusions. Use of appropriate factors like FFPs, Cryoprecipitate during massive transfusions |
| Hypocalcaemia | Consumption with coagulopathy and bound to citrate added to transfused units | Monitor and replace calcium as necessary |
| Hypomagnesaemia | Bound to citrate in transfused units | Monitor and replace magnesium as necessary |
| Citrate toxicity | Citrate is added to stored units as an anticoagulant | Monitor for acidosis during massive transfusions |
| Lactic acidosis | Hyperlactataemia due to anaerobic metabolism in stored units | Monitor for acidosis during massive transfusions |
| Hyperkalaemia | Potassium migrates from stored erythrocytes into plasma whilst in storage | Careful monitoring and usage of products within a specified period |
| Air embolism | Inadvertent infusion | Careful monitoring, use of transfusion sets with air vents, filters |
JC / Sakurai 2019
Exam appearances
| Exam | Exact wording | Relationship | Success |
|---|---|---|---|
| 2020A Q03 | Outline the potential adverse consequences of blood transfusion. | historical_member | — |
| 2013B Q13 | Outline the adverse consequences of a blood transfusion. (75% of marks) Define massive blood transfusion and list the adverse consequences associated with a massive blood transfusion. (25% of marks) | historical_member | — |
| 2017A Q16 | List the potential problems resulting from blood transfusion and methods used to minimise them. | historical_member | — |
| 2025B Q06 | Outline the potential adverse consequences of blood product transfusion including the underlying mechanisms. | variant | 16.00% |
| 2026A Q06 | Outline the potential adverse effects of red blood cell transfusion. Effects secondary to massive transfusion are NOT required. | variant | 53.00% |