1. Department of Anesthesiology and Critical Care and
2. Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, Pennsylvania;
3. Division of Pulmonary, Critical Care, and Sleep Medicine, University of Miami Miller School of Medicine, Miami, Florida;
4. Division of Critical Care Medicine, Albert Einstein College of Medicine, Bronx, New York;
5. Department of Critical Care Medicine, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada;
6. Department of Anesthesia and
7. Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada; and
8. Division of Pulmonary, Allergy, Sleep and Critical Care Medicine, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts