[1] Univ Melbourne, Melbourne Med Sch, Dept Crit Care, Melbourne, Vic, Australia
[2] Royal Melbourne Hosp, Dept Anaesthesia & Pain Management, Melbourne, Vic, Australia
[3] Chinese Univ Hong Kong, Prince Wales Hosp, Dept Anaesthesia & Intens Care, Hong Kong, Peoples R China
[4] Univ Melbourne, Ctr Epidemiol & Biostat, Melbourne Sch Populat & Global Hlth, Melbourne, Vic, Australia
[5] Univ Melbourne, Fac Med Dent & Hlth Sci, Methods & Implementat Support Clin & Hlth MISCH R, Melbourne, Vic, Australia
[6] Melbourne Sch Populat & Global Hlth, Hlth Econ Unit, Melbourne, Vic, Australia
[7] Austin Hlth, Dept Anaesthesia, Melbourne, Vic, Australia
[8] Northeast Hlth Wangaratta, Dept Anaesthesia & Pain Management, Wangaratta, Australia
[9] Tuen Mun Hosp, Dept Anaesthesia & Operating Room Serv, Hong Kong, Peoples R China