1. Department of Emergency Medicine, Horsens Regional Hospital, Horsens, Denmark (M.J.H.).
2. Center for Resuscitation Science, Department of Emergency Medicine (M.J.H., S.W., C.E.R., A.K.H.-N., M.W.D., L.W.A.), Beth Israel Deaconess Medical Center, Boston, MA.
3. Research Center for Emergency Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, Denmark (M.J.H., L.W.A.).
4. Department of Cardiology, Copenhagen University Hospital, Denmark (S.W.).
5. Division of Medical Critical Care, Department of Pediatrics (C.E.R.), Boston Children’s Hospital, Harvard Medical School, MA.
6. Division of Critical Care Medicine, Department of Anesthesiology, Critical Care and Pain Medicine (M.K.), Boston Children’s Hospital, Harvard Medical School, MA.
7. Department of Clinical Research, Center for Prehospital and Emergency Research, Aalborg University, Denmark (A.K.H.-N.).
8. Department of Internal Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine (M.W.D.), Beth Israel Deaconess Medical Center, Boston, MA.