1. Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
2. Department of Medicine, University of Washington–Harborview Center for Prehospital Emergency Care, University of Washington, Seattle
3. Department of Medicine, Saint Luke’s Mid America Heart Institute, Kansas City, Missouri
4. Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia
5. Veteran Affairs Eastern Colorado Health Care System, Denver6Department of Medicine, University of Colorado School of Medicine, Aurora