[1] Univ Iowa, Roy J & Lucille A Carver Coll Med, Iowa City, IA USA
[2] Unity Point Hlth Trinity, Dept Emergency Med, Rock Isl, IL USA
[3] Merck & Co Inc, North Wales, PA 19454 USA
[4] Univ Iowa, Coll Publ Hlth, Dept Biostat, Iowa City, IA USA
[5] Washington Univ St Louis, Dept Emergency Med, Sch Med, St Louis, MO USA
[6] Univ Virginia, Sch Med, Dept Internal Med, Charlottesville, VA USA
[7] Univ Iowa Hosp & Clin, Dept Anesthesia, Iowa City, IA 52242 USA
[8] Univ Iowa Hosp & Clin, Dept Resp Care, Iowa City, IA USA
[9] Univ Iowa Hosp & Clin, Dept Internal Med, Div Pulm Crit Care & Occupat Med, Iowa City, IA 52242 USA
[10] Washington Univ, Sch Med, Dept Anesthesiol, St Louis, MO USA
[11] Univ Iowa, Hosp & Clin, Dept Emergency Med, Iowa City, IA USA
[12] Univ Iowa, Dept Epidemiol, Coll Publ Hlth, Iowa City, IA USA