A convincing, practice-changing trial is a rare thing in major trauma, but here comes a biggie:
The CRASH-2 trial recruited over 20 000 patients from 40 countries (sadly excluding the US because the trial investigators couldn’t afford the insurance – a sign that no large drug company was funding this trial of an inexpensive therapy).
The antifibrinolytic drug tranexamic acid was compared with placebo in adult trauma patients with, or thought to be at risk of, significant haemorrhage. Clinicians were blinded to the intervention and the primary outcome was death in hospital within 4 weeks of injury. Secondary outcomes were vascular occlusive events (myocardial infarction, stroke, pulmonary embolism, and deep vein thrombosis), surgical intervention (neurosurgery, thoracic, abdominal, and pelvic surgery), receipt of blood transfusion, and units of blood products transfused. Treatment groups were balanced with respect to all baseline patient characteristics.

All-cause mortality was significantly reduced with tranexamic acid and the risk of death due to bleeding was significantly reduced. Vascular occlusive events (fatal or non-fatal) did not differ significantly between the groups (and were fewer in the tranexamic acid group compared with the placebo group).
All cause mortality in the tranexamic acid group was (1463/10 060) = 14·5% and in the placebo group was (1613/10 067) = 16·0%. So absolute risk reduction is 1.5% and Number Needed to Treat = 67.
The same trials group is investigating the effect of tranexamic acid in post-partum haemorrhage, in a study known as the WOMAN Trial
Take Home Message: the early administration of tranexamic acid to trauma patients with, or at risk of, significant bleeding reduces the risk of death from haemorrhage with no apparent increase in fatal or non- fatal vascular occlusive events. All-cause mortality was significantly reduced with tranexamic acid.
Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial
The Lancet, Early Online Publication, 15 June 2010