1. Department of Emergency Medicine, University of North Carolina, Carrboro, North Carolina, USA
2. School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
3. Department of Emergency Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
4. Department of Emergency Medicine, Weill Cornell Medicine/NewYork-Presbyterian Hospital, New York, New York, USA
5. Department of Biostatistics and Epidemiology, University of North Texas Health Science Center, Fort Worth, Texas, USA