[1] Johns Hopkins Univ, Sch Med, Dept Emergency Med, Baltimore, MD 21218 USA
[2] Burke Cty EMS, Chapel Hill, NC USA
[3] Univ N Carolina, Sch Med, Chapel Hill, NC USA
[4] Durango Fire Dept Rescue, Durango, TX USA
[5] EMS, Durango, TX USA
[6] Univ Texas Hlth Sci Ctr San Antonio, Dept Emergency Med, San Antonio, TX 78229 USA
[7] Wake Forest Baptist Hlth, Dept Emergency Med, Wake Forest, NC USA
[8] Jefferson Hills Area Ambulance, Pittsburgh, PA USA
[9] Jackson Hole Fire & EMS Natl Pk Serv, Seattle, WA USA
[10] Univ Washington, Sch Med, Seattle, WA USA