ABC of transfusion. Massive blood transfusion.

5 Maintain plasma colloid osmotic pressure "Massive transfusion" is arbitrarily defined as the replacement of the patient's total blood volume by stored homologous bank blood in less than 24 hours. It is a medical emergency, usually occurring in the accident department, the operating theatre, or the obstetric department, when a patient presents with overwhelming haemorrhage and acute hypovolaemic shock. Rapid loss of large quantities of blood impairs tissue perfusion and requires urgent correction. Management comprises prompt resuscitation to maintain circulating blood volume, the oxygen carrying capacity of blood, haemostasis, colloid osmotic pressure, and plasma biochemical balance. The morbidity and mortality from massive transfusion are high, not because ofthe transfusion itself but because of the underlying reason for the haemorrhage and any pre-existing diseases. Patients who have massive haemorrhages do not form a uniform group and cannot be expected to behave in similar ways. Prolonged shock, hypotension, extensive tissue damage, and obstetric complications can all predispose to disseminated intravascular coagulation, which must be recognised and treated. Pre-existing liver or renal disease can exacerbate the complications of massive transfusion, as there may already be abnormalities of haemostasis