1. Department of Emergency Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, New York
2. Department of Anesthesiology, Columbia University College of Physicians and Surgeons, New York, New York
3. Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora
4. Department of Epidemiology, Columbia University Mailman School of Public Health, New York, New York