[1] Royal Melbourne Hosp, Dept Intens Care, Melbourne, Vic 3050, Australia
[2] Univ Melbourne, Ctr Integrated Crit Care, Melbourne, Vic, Australia
[3] Monash Univ, Australian & New Zealand Intens Care Res Ctr, Dept Epidemiol & Prevent Med, Melbourne, Vic, Australia
[4] Univ Melbourne, Data Analyt Res & Evaluat Ctr, Melbourne, Vic, Australia
[5] Austin Hosp, Melbourne, Vic, Australia
[6] Med Res Inst New Zealand, Wellington, New Zealand
[7] Dalhousie Univ, Div Geriatr Med, Halifax, NS, Canada
[8] Dalhousie Univ, Div Neurol, Halifax, NS, Canada
[9] Dalhousie Univ, Geriatr Med Res Unit, Div Geriatr Med, Dept Med, Halifax, NS, Canada
[10] Nova Scotia Hlth Author, Halifax, NS, Canada
[11] Alfred Hosp, Dept Intens Care, Melbourne, Vic, Australia
[12] Australian & New Zealand Intens Care Soc, Ctr Outcome & Resource Evaluat, Melbourne, Vic, Australia