1 Eastern Health Intensive Care Research, Box Hill Hospital, Box Hill, VIC 3128, Australia; Faculty of Medicine, Nursing, and Health Sciences, Monash University, Clayton, VIC, Australia. Electronic address: graeme.duke@easternhealth.org.au.
2 Department of Intensive Care Medicine, The Queen Elizabeth Hospital, Woodville, SA, Australia.
3 Department of Critical Care Medicine, St Vincent's Hospital, Fitzroy, VIC, Australia.
4 Department of Intensive Care, Alfred Hospital, Prahran, VIC, Australia; Australian and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation, Carlton, VIC, Australia.