In adults, massive transfusion can be defined as replacement of >1 blood volume in 24 hours or >50% of blood volume in 4 hours (adult blood volume is approximately 70 mL/kg).
In children, it can be defined as transfusion of >40 mL/kg (blood volume in children over 1 month old is approximately 80 mL/kg).
Massive transfusion occurs in settings such as severe bleeding due to trauma, ruptured aortic aneurysm, surgery and obstetrics complications. The goals to the management of massive transfusion include:
- early recognition of blood loss
- maintenance of tissue perfusion and oxygenation by restoration of blood volume and haemoglobin (Hb)
- arrest of bleeding including with early surgical or radiological intervention, and
- appropriate use of blood component therapy to manage coagulopathy.
Massive transfusion management is guided by regular clinical and laboratory assessment according to institutional guidelines. It’s important to prevent hypothermia and acidosis. Tranexamic acid is often indicated early in management.
Institutional guidelines may recommend laboratory monitoring of coagulation, acid-base and blood counts during treatment. Viscoelastic testing, such as TEG and ROTEM, are now commonly used to guide blood component administration. The national PBM guidelines on critical bleeding management give further advice: Massive Transfusion Protocol (MTP).
Indications for blood components in massive transfusion
- Red cell transfusion is likely to be required when 30–40% blood volume is lost (approximately 2,000 mL in an adult); >40% blood volume loss is immediately life-threatening.
- Pretranfusion compatibility testing should be done early.
- It’s best practice to transfuse red cells of the same ABO and RhD group as the patient, however if there are insufficient supplies of the patient's ABO group available locally, red cells of another ABO compatible group may be released by the Transfusion Service Provider.
- In an emergency situation, uncrossmatched Group O RhD negative red cells (especially for females of childbearing age) may be appropriate.
- Should be given through a blood warmer.
Fresh frozen plasma (FFP)
- Give FFP to maintain PT & APTT ≤ 1.5x the normal range, or according to institutional viscoelastic testing algorithm.
- Usual dose is 15 ml/kg.
- If the patient's blood group is unknown, give group AB or group A FFP according to jurisdictional guidelines.
- Allow 1/2 hour thawing time.
- FFP will not provide adequate fibrinogen to correct hypofibrinogenemia in a critically bleeding patient. Cryoprecipitate should be used.
- In obstetrics haemorrhage, early DIC is often present so consider cryoprecipitate early in this situation.
- Usual dose is 3–4 g of fibrinogen which is roughly equivalent to 10 units of whole blood cryoprecipitate or 5 units of apheresis cryoprecipitate - your local Transfusion Service Provider can advise on the number of units to provide this dose.
- Allow up to 1/2 hour thawing time.
- Thrombocytopenia <50 x 109 /L can be anticipated after two blood volume replacement due to dilution and increased consumption.
- Aim to keep the platelet count >50 x 109 /L (or >100 x 109/L in situations such as CNS injury or diffuse microvascular bleeding).
- The usual dose in an adult is 1 unit.
Patients on warfarin
For life-threatening (critical organ) and clinically significant bleeds, the consensus is to use a combination of Prothrombinex-VF, Vitamin K and FFP.
- Vitamin K1: 5–10 mg IV
- Prothrombinex (PTX-VF): 50 IU/kg
- Fresh frozen plasma: 150–300 mL or 15 mL/kg if Prothrombinex-VF not available
Note that the use of blood components in patients with critical bleeding is lifesaving, but increased volumes may be independently associated with mortality and ARDS.