1. Division of Pulmonary and Critical Care Medicine, School of Medicine,
2. Department of Epidemiology, Bloomberg School of Public Health, and
3. Outcomes After Critical Illness and Surgery Group, Johns Hopkins University, Baltimore, Maryland;
4. Division of Pulmonary, Allergy and Critical Care, Department of Medicine, and
5. Department of Medical Ethics and Health Policy, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; and
6. Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, Pennsylvania