1. Department of Emergency Medicine, Center for Resuscitation Science, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
2. School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania.
3. Leonard Davis Institute of Health Economics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
4. Section of Pulmonary Allergy and Critical Care, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.