Karen Smith1, Stephen Bernard2. 1. Ambulance Victoria, Melbourne, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia; Emergency Medicine, University Western Australia, Perth, Western Australia, Australia. Electronic address: karen.smith@ambulance.vic.gov.au. 2. Ambulance Victoria, Melbourne, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia; Alfred Hospital, Melbourne, Australia.