1. Department of Emergency Medicine, University of Kentucky, Lexington, Kentucky, USA
2. Department of Emergency Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
3. Department of Emergency Medicine, University of Tennessee College of Medicine, Chattanooga, Tennessee, USA
4. University of Alabama, School of Medicine, USA
5. Department of Epidemiology, University of Alabama at Birmingham, USA
6. Department of Emergency Medicine, University of Alabama School of Medicine, USA