Massive transfusion is typically used to treat life-threatening major haemorrhage and for adults has various definitions, including, replacement of:
- more than one blood volume in 24 hours
- > 50% of blood volume in four hours
- ≥ five units of red blood cells in four hours
When to suspect this reaction
Massive transfusion may result in metabolic and haemostatic abnormalities. Metabolic abnormalities can cause cardiac arrhythmia or cardiac arrest. Massive transfusion is an independent risk factor for developing multi-organ failure.
Some of the complications of massive transfusion include:
- hypothermia
- haemostatic abnormalities including dilutional coagulopathy and disseminated intravascular coagulation
- citrate toxicity resulting in hypocalcaemia
- metabolic acidosis
- hyperkalaemia and hypokalaemia
- immune haemolysis from an increased risk of ABO-incompatible red cell transfusions or ABO incompatibility from large amounts of plasma
- alloimmunisation and delayed haemolytic transfusion reactions
- volume overload/over transfusion
- air embolism
Usual causes
Complications of massive transfusion are dependent on the number of units transfused, rate of transfusion and various patient factors.
Investigations
Monitor the patient’s core temperature and keep it above ≥ 35°C.
Monitor electrolytes including potassium, ionised calcium and acid base status.
Watch for dilutional coagulopathy by frequent measuring of platelet count, INR/APPT and fibrinogen.
Consider Viscoelastic haemostatic assays (VHA) where appropriate and cardiac monitoring.
What to do
Massive transfusion should follow the national https://www.blood.gov.au/patient-blood-management-guideline-adults-critical-bleeding and your institutional protocols.
Use blood warmers where appropriate.
Consider calcium replacement and use of tranexamic acid.
Updated September 2026