1. Department of Emergency Medicine and
2. Division of Pulmonary, Allergy, Critical Care, and Sleep, Department of Medicine, University of Arizona, Tucson, Arizona
3. Department of Anesthesiology and Department of Emergency Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
4. Department of Emergency Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts; and
5. Department of Critical Care Medicine, University of Alberta, Edmonton, Alberta, Canada