1. Yong Loo Lin School of Medicine National University of Singapore Singapore, Singapore
2. Health Services Research Centre Singapore Health Services Academia, 20 College Road 169856 Singapore, Singapore
3. Duke-NUS Medical School National University of Singapore Singapore, Singapore
4. Department of Emergency Medicine Singapore General Hospital Singapore, Singapore
5. Department of General Surgery Singapore General Hospital Singapore, Singapore
6. Department of Emergency and Critical Care Medicine Nippon Medical School Tokyo, Japan
7. Health Services Research Unit Singapore General Hospital Singapore, Singapore