A 36-year-old man is involved in a serious road traffic accident. On arrival at the emergency unit he is unconscious and shocked. After initial resuscitation, including the administration of physiological saline and synthetic colloids, X-rays and a computed tomography scan quickly establish that he has fractures of the right femur and pelvis, a right-sided haemothorax and haemoperitoneum with subdiaphragmatic gas. Baseline haematology (before transfusion) shows haemoglobin (Hb) 12.6 g/dl (reference range 13.5–18.0 g/dl) and platelets 140 × 109/l (150–400 × 109/l). A coagulation screen shows prothrombin time (PT) 15 seconds (control 12 seconds), activated partial thromboplastin time (APTT) 42 seconds (control 32 seconds) and fibrinogen 2.0 g/l (reference range 2.0–4.5 g/l). Laparotomy shows a ruptured spleen, jejunal transection and profuse bleeding. There are bilateral large subdural haematomas. Despite surgical intervention, the patient continues to bleed rapidly into the abdominal and chest cavities and, over the next 4 hours, he receives 20 units of red cells, two adult therapeutic doses (8 units) of platelets and 4 units of fresh frozen plasma. At this point he is oozing blood from previously haemostatic surgical wounds and intravenous catheter sites, systolic blood pressure is falling again and urine output is decreasing. Repeat blood tests show Hb 6.3 g/dl, white blood cells 5.0 × 109/l, platelets 50 × 109/l, PT 25 seconds, APTT 64 seconds and fibrinogen 0.8 g/l. A blood film is reported as showing fragmented red cells.
What is your interpretation of the haematological and coagulation changes described above?
How would you define massive blood loss?
What are the key features of a massive blood loss protocol and of the management of the associated haematological problems?
On arrival at the emergency unit the patient has a near-normal Hb concentration. However, in the early stages of major acute haemorrhage, the Hb concentration and haematocrit give a poor indication of the degree of blood loss because of haemoconcentration and peripheral vasoconstriction. Both the PT and APTT are only slightly prolonged but, of note, the fibrinogen concentration is at the low limit of normal. Fibrinogen is an acute-phase reactant protein and one would expect the level to be markedly elevated in a patient with severe tissue injury. This, taken together with the slight thrombocytopenia, suggests that excessive consumption of clotting factors and platelets is already occurring.
By the time the blood tests are repeated, there is marked prolongation of PT and APTT and significant thrombocytopenia and hypofibrinogenaemia. The presence of fragmented red cells in the blood film and the clinical picture of generalized bleeding are indicative of disseminated intravascular coagulation (DIC).
Management of massive blood loss and transfusion
Massive blood loss is defined as the loss of more than one blood volume within 24 hours (around 70 ml/kg, or 5 litres in a 70 kg adult), 50% of total blood volume ...