[1] Aarhus Univ Hosp, Res Ctr Emergency Med, Norrebrogade 44,Bygning 30,1 Sal, DK-8000 Aarhus C, Denmark
[2] Beth Israel Deaconess Med Ctr, Dept Emergency Med, Boston, MA 02215 USA
[3] Aarhus Univ Hosp, Dept Anesthesiol, Aarhus, Denmark
[4] Med City Childrens Hosp, Div Cardiac Crit Care, Dept Pediat, Dallas, TX USA
[5] Childrens Hosp Philadelphia, Dept Anesthesiol Crit Care, Philadelphia, PA 19104 USA
[6] Univ Penn, Perelman Sch Med, Philadelphia, PA 19104 USA
[7] Univ Penn, Perelman Sch Med, Dept Anesthesiol & Crit Care, Philadelphia, PA 19104 USA
[8] Univ Penn, Dept Emergency Med, Philadelphia, PA 19104 USA
[9] Charite, Inst Publ Hlth, Berlin, Germany
[10] Beth Israel Deaconess Med Ctr, Dept Med, Div Pulm & Crit Care Med, Boston, MA 02215 USA