Fleisher & Ludwig’s Textbook of Pediatric Emergency Medicine Eighth Edition Senior Editors Kathy N Shaw, MD, MSCE Professor and Associate Chair Department of Pediatrics Perelman School of Medicine at the University of Pennsylvania The Nicholas Crognale Endowed Chair in Emergency Medicine The Children’s Hospital of Philadelphia Philadelphia, Pennsylvania Richard G Bachur, MD Chief, Division of Emergency Medicine Professor of Pediatrics and Emergency Medicine Department of Pediatrics Division of Emergency Medicine Boston Children’s Hospital/Harvard Medical School Boston, Massachusetts Associate Editors James M Chamberlain, MD Division Chief Department of Emergency Medicine Children’s National Hospital Professor of Pediatrics and Emergency Medicine George Washington University School of Medicine and Health Sciences Washington, DC Jane Lavelle, MD