Current management of coagulopathic, haemorrhaging trauma patients comprises the unguided transfusion of large volumes of red blood cells and clotting product supplements. Without rapidly available and validated diagnostics, products are delivered empirically to patients blind to the type and severity of TIC they may have or indeed even if they do not have TIC. This study will compare outcomes of viscoelastic haemostatic assay (VHA)-guided resuscitation versus conventional management of critically bleeding trauma patients. The hypothesis is that goal-directed haemostatic resuscitation of coagulopathic bleeding trauma patients will yield improved outcomes and reduced blood product demand, compared to empiric massive transfusion therapy.