1. Sanford School of Public Policy, Duke University, Durham, NC, USA
2. Duke-Robert J. Margolis, MD, Center for Health Policy, Duke University, Durham, NC, USA
3. Division of Pulmonary Critical Care, Department of Medicine, Duke University Medical Center, Durham, NC, USA
4. Division of Trauma and Critical Care and Acute Care Surgery, Department of Surgery, Duke University Medical Center, Durham, NC, USA