[1] Univ Colorado, Sch Med, Denver, CO USA
[2] Colorado Emergency Med Res Ctr, Denver, CO USA
[3] Virginia Commonwealth Univ, Richmond, VA 23284 USA
[4] Ohio State Univ, Dept Emergency Med, Columbus, OH 43210 USA
[5] Univ Arizona, Dept Emergency Med, Tucson, AZ 85721 USA
[6] Johns Hopkins Univ, Sch Med, Dept Neurol, Baltimore, MD 21218 USA
[7] Johns Hopkins Univ, Sch Med, Dept Anesthesiol Crit Care Med, Baltimore, MD 21218 USA
[8] Johns Hopkins Univ, Sch Med, Dept Neurosurg, Baltimore, MD 21218 USA
[9] William Beaumont Hosp, Dept Cardiol, Beaumont, TX USA
[10] Univ So Calif, Dept Emergency Med, Los Angeles, CA 90089 USA
[11] Wayne State Univ, Dept Emergency Med, Detroit, MI 48202 USA