4-factor prothrombin complex concentrate (PCC) for trauma (PROCOAG trial). 4-factor PCC rapidly replaces blood clotting proteins which are absent from transfused blood. PCC could therefore be helpful when co-administered with packed red blood cells in large volume transfusions. Among 324 patients with trauma and life-threatening bleeding at 12 French hospitals who were randomized to receive 1ml/kg PCC or placebo, there was no reduction observed in 24-hour blood transfusion needs in the PCC group. PCC was associated with a significantly higher risk for thromboembolic complications (35% vs 24%).