1. Emergency Medicine and Trauma Center, Children’s National Medical Center, Washington, District of Columbia; and
2. Division of Emergency Medicine, Department of Pediatrics,
3. Department of Anesthesia and Critical Care Medicine,
4. Center for Simulation, Advanced Education and Innovation,
5. Department of Cardiology,
6. Center for Injury Research and Prevention, and
7. Biostatistics and Data Management Core, Children’s Hospital of Philadelphia–Westat, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania