1 Department of Emergency Medicine, Singapore General Hospital, Singapore, Singapore; Pre-hospital and Emergency Research Centre, Duke-NUS Medical School, Singapore, Singapore.
2 Health Services Research Centre, SingHealth, Singapore, Singapore.
3 Department of Emergency Medicine, Singapore General Hospital, Singapore, Singapore; Health Services and Systems Research, Duke-NUS Medical School, Singapore, Singapore. Electronic address: marcus.ong.e.h@singhealth.com.sg.