[1] Univ Maryland, Sch Med, Dept Emergency Med, 110 South Paca St,6th Floor,Suite 200, Baltimore, MD 21201 USA
[2] Med Univ South Carolina, Dept Emergency Med, Charleston, SC 29425 USA
[3] MedStar Washington Hosp Ctr, Dept Emergency Med, Washington, DC USA
[4] Georgetown Univ, Sch Med, Washington, DC USA