1 Department of Emergency Medicine, University of North Carolina, 100 Manning Dr. Chapel Hill, NC 27599, United States of America.
2 Department of Emergency Medicine, Wake Forest School of Medicine, 475 Vine St., Winston-Salem, NC 27101, United States of America; North Carolina Office of Emergency Medical Services, 2707 Mail Service Center, Raleigh, NC 27699, United States of America.
3 Department of Emergency Medicine, University of North Carolina, 100 Manning Dr. Chapel Hill, NC 27599, United States of America. Electronic address: [email protected].