1. Department of Respiratory and Critical Care Medicine, Changi General Hospital, Singapore
2. Department of Sleep Medicine, Surgery and Science, Changi General Hospital, Singapore
3. Department of Rehabilitative Services, Physiotherapy, Changi General Hospital, Singapore
4. Department of Nursing, Changi General Hospital, Singapore
5. Department of Health Services Research, Changi General Hospital, Singapore
6. Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
7. Sydney Medical School, University of Sydney, Camperdown, NSW, Australia