[1] Univ Cincinnati, Dept Emergency Med, Cincinnati, OH 45267 USA
[2] Brigham & Womens Hosp, Div Cardiol, Boston, MA 02115 USA
[3] Univ Toronto, Univ Hlth Network, Div Pulm Crit Care, Toronto, ON, Canada
[4] Massachusetts Eye & Ear Infirm, Dept Otol & Laryngol, Boston, MA 02114 USA
[5] Univ Ottawa, Dept Otolaryngol, Ottawa, ON, Canada
[6] Vanderbilt Univ, Dept Emergency Med, Nashville, TN USA