1 Emergency Department, Perth Children's Hospital, Perth, Western Australia, Australia.
2 School of Nursing, Midwifery and Paramedicine, Curtin University, Perth, Western Australia, Australia.
3 Division of Paediatrics and Emergency Medicine School of Medicine and Health Sciences, University of Western Australia, Perth, Western Australia, Australia.
4 Emergency Medicine, Royal Children's Hospital, Melbourne, Victoria, Australia.
5 Emergency Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia.
6 Department of Paediatrics, Faculty of Medicine, Dentistry, and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia.
7 Paediatric Emergency Medicine Centre of Research Excellence, Melbourne, Victoria, Australia.
8 Children's Emergency Department, Starship Children's Hospital, Auckland, New Zealand.
9 Department of Surgery and Paediatrics, Child and Youth Health, University of Auckland, Auckland, New Zealand.