1 Department of Anaesthesia, Prince of Wales Hospital, Sydney, NSW, Australia; School of Medicine, Randwick Clinical Campus, UNSW Medicine, Sydney, NSW, Australia. Electronic address: steven.cai@unsw.edu.au.
2 Department of Anaesthesia, Auburn Hospital, Sydney, NSW, Australia; School of Medicine, University of Notre Dame, Sydney, NSW, Australia.
3 Department of Anaesthesia Perioperative Medicine and Pain Management, Canberra Hospital, Canberra, ACT, Australia; College of Health and Medicine, Australian National University, Canberra, ACT, Australia; School of Medicine, The University of Sydney, Sydney, NSW, Australia.