Fleisher & Ludwig's textbook of pediatric emergency medicine / 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, Professor of Pediatrics, Associate Professor of Emergency Medicine, Harvard Medical School, Chief, Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts ; associate editors, James M. Chamberlain, MD, Division Chief, Department of Emergency Medicine, Children's National Health System, Professor of Pediatrics and Emergency Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, Jane Lavelle, MD, Associate Professor of Pediatrics, Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Medical Director, Associate Division Chief, Emergency Medicine, Medical Director, Pathway Program, Office of Continous Quality Improvement, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, Joshua Nagler, MD, MHPEd, Assistant Professor of Pediatrics and Emergency Medicine, Harvard Medical School, Fellowship Director and Director of Medical Education, Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, Joan E. Shook, MD, Professor, Department of Pediatrics, Baylor College of Medicine, Chief Safety Officer and Chief Clinical Information Officer, Texas Children's Hospital, Houston, Texas.