1 Division of Emergency Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
2 Department of Pediatrics, Section of Pediatric Hospital Medicine, Children's Hospital Colorado, University of Colorado, Aurora, Colorado, USA.
3 Department of Pediatrics, Section of Emergency Medicine, Children's Hospital Colorado, University of Colorado, Aurora, Colorado, USA.
4 Department of Pediatrics, Sections of Emergency Medicine and Hospital Medicine, Children's Hospital Colorado, University of Colorado, Aurora, Colorado, USA.