1 Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Level 8, NUHS Tower Block, 1E Kent Ridge Road, 119228, Singapore. Electronic address: jun_jie_ng@nuhs.edu.sg.
2 Yong Loo Lin School of Medicine, National University of Singapore, Level 11, NUHS Tower Block, 1E Kent Ridge Road, 119228, Singapore.
3 Department of Anaesthesia, National University Hospital, 5 Lower Kent Ridge Road, 119075, Singapore.
4 Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Level 8, NUHS Tower Block, 1E Kent Ridge Road, 119228, Singapore.