[1] George Washington Univ, Childrens Natl Med Ctr, Div Emergency Med, Washington, DC USA
[2] NYU, Sch Med, Dept Emergency Med, Div Pediat Emergency Med, New York, NY USA
[3] Univ Botswana, Sch Med, Dept Emergency Med, Gaborone, Botswana
[4] Univ British Columbia, Dept Emergency Med, Vancouver, BC V5Z 1M9, Canada
[5] St Pauls Hosp, Vancouver, BC V6Z 1Y6, Canada