1. Health Services & Systems Research, Duke-NUS Medical School, Singapore 169857, Singapore
2. Department of Emergency Medicine, Singapore General Hospital, Singapore 168753, Singapore
3. Center for Community Health Integration, Case Western Reserve University, Cleveland, OH 44106, USA
4. Home Team Medical Services Division, Ministry of Home Affairs, Singapore 329560, Singapore
5. Emergency Medicine Department, National University Hospital, National University Health System, Singapore 119074, Singapore
6. Pre-Hospital & Emergency Research Centre, Duke-NUS Medical School, Singapore 169857, Singapore