1. NHS Greater Glasgow and Clyde
2. School of Medicine, Dentistry and Nursing, and
3. Division of Pulmonary, Allergy, and Critical Care Medicine, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
4. Department of Physiotherapy, Western Health, Melbourne, Victoria, Australia
5. Library, University of Glasgow, Glasgow, United Kingdom
6. Division of Pulmonary & Critical Care, Department of Medicine, University of Michigan, Ann Arbor, Michigan
7. Center for Clinical Management Research, VA Ann Arbor Healthcare System, Ann Arbor, Michigan; and
8. Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria, Australia