1. Center for Trauma and Critical Care, Department of Surgery, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
2. Clinical Epidemiology and Biostatistics, School of Medical Sciences, Orebro University, Orebro, Sweden
3. Department of Surgery, Karolinska University Hospital, Stockholm, Sweden
4. School of Medical Sciences, Orebro University, Orebro, Sweden
5. Division of Trauma and Emergency Surgery, Department of Surgery, Orebro University Hospital, Orebro, Sweden