1 Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: Jerrald.lau@nus.edu.sg.
2 Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
3 Alice Lee Centre for Nursing Studies, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; National University Hospital, Singapore.
4 Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; National University Hospital, Singapore.