1. Department of Trauma Surgery and Critical Care, Creighton University Medical Center, Omaha, NE, USA
2. Department of Surgery, Creighton University School of Medicine, Omaha, NE, USA
3. Creighton University School of Medicine, Omaha, NE, USA
4. Division of Clinical Research and Evaluative Sciences, Creighton University School of Medicine, Omaha, NE, USA