[1] Baylor Univ, Med Ctr, Dept Emergency Med, 3500 Gaston Ave, Dallas, TX 75246 USA
[2] Baylor Scott & White Healthcare Syst, Dept Quantitat Sci, Suite 500,8080 North Cent Expressway, Dallas, TX 75206 USA
[3] Indiana Univ Sch Med, Dept Emergency Med, 340 West 10th St, Indianapolis, IN 46202 USA
[4] Indiana Univ Sch Med, Dept Physiol, 340 West 10th St, Indianapolis, IN 46202 USA