[1] Univ New South Wales, South Western Sydney Clin Sch, Sydney, NSW, Australia
[2] Liverpool Hosp, Dept Anaesthesia, Sydney, NSW, Australia
[3] Liverpool Hosp, Dept Emergency Med, Sydney, NSW, Australia
[4] Liverpool Hosp, Dept Orthopaed Surg, Sydney, NSW, Australia
[5] Liverpool Hosp, Dept Geriatr Med, Sydney, NSW, Australia
[6] Ingham Inst, South Western Emergency Res Inst, Sydney, NSW, Australia