1. Division of Pulmonary and Critical Care Medicine, Lahey Hospital and Medical Center, Burlington
2. Tufts University School of Medicine
3. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital
4. Harvard Medical School, Boston, Massachusetts, USA
5. South Central Ambulance Service NHS Foundation Trust, Bicester, Oxfordshire
6. Warwick Medical School, University of Warwick, Coventry, UK
7. Division of Critical Care Medicine, Montefiore Medical Center, the Bronx, New York, USA