Appropriate use of blood transfusion products
Patient Blood Management
- Patient Blood Management: the first question is always whether the transfusion can be avoided
- Treat the cause (iron, B12, folate, EPO), minimise iatrogenic blood loss, use tranexamic acid, cell salvage
- *Transfuse one unit, then reassess.* A number alone is never an indication
Components from one whole blood donation
| Component | Volume | Contains | Storage |
|---|---|---|---|
| Packed red cells | ~250-300 mL | Hct ~0.55-0.65, ~250 mg iron per unit | 2-6 C, 42 days |
| Platelets | ~200-350 mL | Pooled (4 donors) or apheresis | 20-24 C with agitation, 5 days (bacterial risk) |
| Fresh frozen plasma | ~250-300 mL | All coagulation factors | -25 C, 12 months; use within 24 h of thawing |
| Cryoprecipitate | ~30-40 mL | Fibrinogen, factor VIII, factor XIII, von Willebrand factor, fibronectin | -25 C, 12 months |
- *All Australian cellular components are universally leucodepleted*
- Expected increments: 1 unit red cells -> Hb +10 g/L; 1 adult platelet dose -> platelets +20-40 x10^9/L; FFP 15 mL/kg -> ~25% factor rise
Use in Australia
- ~800,000 red cell units issued annually in Australia; demand per capita falling as PBM programs mature
- ~1 in 30 Australians receives a transfusion each year
- Residual viral transmission risk in Australia is extremely low - HIV and HCV <1 in a million; HBV ~1 in 1 million
- Bacterial contamination of platelets is now the leading infectious risk (~1 in 30,000-75,000)
- TACO is the commonest cause of transfusion-related death reported to haemovigilance schemes
Why leucodepletion
Residual donor white cells cause most non-infectious hazards. Leucodepletion reduces:
- Febrile non-haemolytic transfusion reactions
- HLA alloimmunisation and platelet refractoriness
- CMV transmission (leucodepleted is accepted as CMV-"safe", equivalent to CMV-seronegative for most indications)
- Bacterial contamination load
- Transfusion-related immunomodulation (implicated in cancer recurrence and postoperative infection)
- Theoretical vCJD transmission
- *It reduces but does NOT eliminate transfusion-associated GVHD - only irradiation does that*
Why irradiation
- Gamma or X irradiation (25 Gy) inactivates donor T lymphocytes
- Prevents transfusion-associated GVHD - donor T cells engraft in an immunocompromised or HLA-haplotype-sharing recipient, attack marrow, >90% mortality
- Cost: potassium leaks from irradiated red cells -> shortened shelf life to 14 days; platelets keep their normal 5-day expiry
### Who needs irradiated products
- Hodgkin lymphoma - lifelong, at any stage of disease
- Allogeneic and autologous stem cell transplant recipients (and from the time of stem cell harvest)
- Purine analogues (fludarabine, cladribine, bendamustine) and alemtuzumab, ATG - often lifelong
- Acute leukaemia, NHL, T-cell malignancy; high-dose chemotherapy or prolonged high-dose corticosteroid for malignancy
- Aplastic anaemia on immunosuppression; B-cell malignancy therapy causing lymphopenia
- Intrauterine transfusion, neonatal exchange transfusion, premature infants
- Directed donations from blood relatives (shared haplotype - the highest-risk scenario), HLA-matched platelets
- Congenital T-cell immunodeficiency (DiGeorge, SCID)
- Solid organ transplant recipients
- *HIV alone is NOT an indication*
Washed products
- Removes plasma - for severe recurrent allergic reactions and IgA deficiency with anti-IgA antibodies
Pre-transfusion testing
- Group and screen: ABO/RhD group + antibody screen against a panel of known red cells
- Crossmatch: electronic (if no antibodies and a validated system) or serological (indirect antiglobulin/Coombs)
- *Two independently collected samples confirming group before non-emergency transfusion* for a first-time patient
- Positive antibody screen -> antibody identification -> antigen-negative units -> delay. Alert the lab early
Emergency release
| Time available | Product |
|---|---|
| Immediate | O RhD-negative (O RhD-positive acceptable for males and post-menopausal females - conserves scarce O-negative stock) |
| ~10-15 min | Group-specific, uncrossmatched |
| ~45 min | Fully crossmatched |
Administration and monitoring
- *Positive patient identification at the bedside is the single most important safety step* - ABO-incompatible transfusion is almost always a clerical error
- Baseline observations, then at 15 minutes, and at completion
- One unit over 2-4 hours (must complete within 4 hours of leaving controlled storage)
- Only 0.9% sodium chloride in the same line - no glucose (haemolysis) and no calcium-containing fluid such as Hartmann's (clot formation)
Red cells - thresholds
A. Red cells - thresholds
| Setting | Trigger |
|---|---|
| Most hospitalised, haemodynamically stable adults | Hb <70 g/L |
| Cardiac surgery, most surgical patients | Hb <75-80 g/L |
| Acute myocardial infarction | *Liberal strategy: transfuse for Hb <100 g/L - AABB 2025 following MINT. A reversal of previous restrictive advice* |
| Chronic transfusion-dependent anaemia (thalassaemia) | Programme-specific; pre-transfusion Hb ~95-100 g/L |
| Active major haemorrhage | Clinical, not numeric - major haemorrhage protocol |
- Hb 70-100 g/L: transfusion not automatically indicated - decide on symptoms, cardiac reserve and ongoing loss
- *Do not transfuse iron-deficiency anaemia that can be corrected with iron* unless there is haemodynamic compromise or active bleeding
- Single-unit policy in non-bleeding patients
Platelets
B. Platelets
| Setting | Target (x10^9/L) |
|---|---|
| Prophylaxis in marrow failure/chemotherapy | >=10 |
| Sepsis, coagulopathy, minor procedure, central line | >=20 |
| Major surgery, lumbar puncture, epidural | >=50 |
| Neurosurgery, posterior eye surgery | >=100 |
| Massive haemorrhage | >=50 (>=100 if CNS injury) |
- *Contraindicated (unless life-threatening bleeding): TTP, HIT, HUS* - fuels thrombosis
- Of little value in ITP (destroyed within minutes) except for major haemorrhage
- RhD-negative women of childbearing potential should receive RhD-negative platelets, or anti-D prophylaxis
FFP
C. FFP
- Bleeding or pre-procedure with PT/INR or APTT >1.5x normal; DIC; massive transfusion; TTP (plasma exchange replacement fluid)
- Dose 15 mL/kg (~4 units in an adult)
- *Not for: warfarin reversal (use prothrombin complex concentrate + vitamin K), volume expansion, "correcting" a mildly abnormal INR in a non-bleeding patient, or nutritional support*
Cryoprecipitate
D. Cryoprecipitate
- Fibrinogen <1.5 g/L with bleeding (obstetric haemorrhage target >2.0); DIC; massive transfusion
- Dose ~10 units (or fibrinogen concentrate where available)
- Factor VIII and VWF content is historical - use specific concentrates for haemophilia A and VWD
Special requirements checklist
E. Special requirements checklist - ask for every patient
1. Irradiated? (list above)
2. CMV-negative? - intrauterine transfusion and neonates; leucodepletion suffices for most others
3. Washed? - severe allergic reactions, IgA deficiency with anti-IgA
4. Phenotyped/antigen-matched? - haemoglobinopathies, chronic transfusion programmes, women of childbearing potential (Rh and Kell matching prevents alloimmunisation and future haemolytic disease of the fetus and newborn)
5. Anti-D required? - RhD-negative recipient of RhD-positive platelets
Iron overload in chronic transfusion
F. Iron overload in chronic transfusion
- ~250 mg elemental iron per red cell unit; no physiological excretion route
- Consider chelation after ~20 units or ferritin >1000 microg/L - deferasirox, deferiprone, desferrioxamine
- *T2 MRI for cardiac and liver iron* - ferritin alone underestimates cardiac loading*
Complications
- Iron overload - cardiac, hepatic and endocrine (chronic transfusion programmes)
- Transfusion-associated GVHD (irradiation prevents)
- TACO and TRALI
- Acute and delayed haemolytic transfusion reactions; hyperhaemolysis in sickle cell disease
- Alloimmunisation - red cell antibodies, HLA antibodies, platelet refractoriness
- Haemolytic disease of the fetus and newborn (anti-D, anti-Kell)
- Post-transfusion purpura (anti-HPA-1a)
- Citrate toxicity and hypocalcaemia; hyperkalaemia (irradiated or older units); hypothermia in massive transfusion
- Transfusion-transmitted infection - bacterial (platelets), viral, malaria, babesia
- Jehovah's Witness and other refusal of blood products - document the specific components and derivatives accepted
Safety of the supply
- Australian blood supply is among the safest in the world
- The dominant residual risks are non-infectious and human
Serious hazards in order of frequency
1. TACO - the commonest cause of transfusion-related death; largely preventable with slower rates, smaller volumes and diuretics
2. Febrile non-haemolytic reactions - common, benign
3. Allergic/urticarial reactions
4. Bacterial contamination (platelets)
5. TRALI - incidence markedly reduced by male-predominant plasma donor policies
6. Acute haemolytic transfusion reaction - rare, but usually fatal-preventable clerical error
7. Transfusion-associated GVHD - rare, >90% mortality
Every reaction requires
- Stop the transfusion, keep the line open with saline, recheck the patient's identity against the unit
- Notify the blood bank; return the unit and giving set; take repeat group and screen, DAT, FBE, LDH, haptoglobin, bilirubin, coagulation screen, blood and unit cultures, and a urine sample for haemoglobinuria
- Report to the haemovigilance programme
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