1 Research Center for Emergency Medicine, Aarhus University Hospital, Denmark; Emergency Department, Randers Regional Hospital, Denmark; Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, United States. Electronic address: kglerup@clin.au.dk.
2 Department of Pediatrics, Cardiac Intensive Care, Medical City Children's Hospital, United States.
3 Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, United States; University of Pennsylvania, Perelman School of Medicine, United States.