All patients arriving to the participating center's trauma emergency department via helicopter directly from the scene will be screened and initial data collected. Of that group, all patients who meet the "highest risk" category (based on vital signs, type of injury, use of tourniquet, and/or intubation) or received blood during transport will be followed through "direct observation" through the initial resuscitation period and then indirectly through medical chart review until hospital discharge or 30 days after admission (whichever occurs first).