1. Division of Hospital Medicine at Children’s National Hospital , and George Washington University of Medicine and Health Sciences , Washington , DC , USA
2. Department of Biostatistics and Study Methodology at Children’s National Hospital , and George Washington University of Medicine and Health Sciences , Washington , DC , USA
3. Division of Emergency Medicine at Children's National Hospital , and George Washington University School of Medicine and Health Sciences , Washington , DC , USA
4. Tufts University School of Medicine and the George W. Hallett MD Chair of Pediatrics at the Barbara Bush Children’s Hospital , Portland , ME , USA