1 Center for Translational Research, Children's National Research Institute, Washington, DC. Electronic address: rmargolis@childrensnational.org.
2 Center for Translational Research, Children's National Research Institute, Washington, DC; Division of Emergency Medicine, Children's National Hospital, Washington, DC.
3 Division of General and Community Pediatrics, Children's National Hospital, Washington, DC.
4 Center for Translational Research, Children's National Research Institute, Washington, DC; George Washington University School of Medicine and Health Sciences, Washington, DC.
5 Center for Translational Research, Children's National Research Institute, Washington, DC.
6 Center for Translational Research, Children's National Research Institute, Washington, DC; Division of Hospital Medicine, Children's National Hospital, Washington, DC.