1. Division of Palliative Medicine, QEII Health Science Centre and Dalhousie University, Halifax, Nova Scotia, Canada.
2. Division of Respirology, QEII Health Science Centre and Dalhousie University, Halifax, Nova Scotia, Canada.
3. Department of Critical Care and Division of Respirology, Sunnybrook Health Sciences Centre and Sunnybrook Research Institute. Interdepartmental Division of Critical Care, University of Toronto, Toronto, Ontario, Canada.