[1] Univ Western Australia, Sch Populat Hlth, Perth, WA, Australia
[2] Curtin Univ, Royal Perth Hosp, Intens Care Med, Perth, WA, Australia
[3] Curtin Univ, Prehosp Emergency Care, Perth, WA, Australia
[4] McGill Univ, Crit Care Med, Montreal, PQ, Canada