1. Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
2. Department of Critical Care, Lakeridge Health Corporation, Oshawa, ON, Canada.
3. Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
4. Cardiothoracic Intensive Care Unit, National University Heart Centre, National University Hospital, Singapore, Singapore.
5. School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada.
6. Department of Anesthesiology and Pain Medicine, University of Ottawa and The Ottawa Hospital, Ottawa, ON, Canada.
7. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.