1. From Center for Resuscitation Science and Department of Emergency Medicine, University of Pennsylvania, Philadelphia (D.G.B., B.S.A.); Division of Pediatric Surgery, Children’s Hospital Los Angeles, Los Angeles, CA (R.V.B.); Keck School of Medicine, University of Southern California, Los Angeles, CA (R.V.B.); Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia (M.Y.N., J.W.R.); Department of Emergency Medicine, University of British...