1. Pediatric Emergency Department, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces. University of the Basque Country, UPV/EHU. Bilbao, Basque Country, Spain
2. Pediatric Emergency Department, Sant Joan de Déu Hospital, Barcelona, Spain
3. Pediatric Emergency Department, Vall d'Hebron University Hospital, Barcelona, Spain
4. Pediatric Emergency Department, Gregorio Marañón University Hospital, Madrid, Spain
5. Pediatric Emergency Department, 12 de Octubre Hospital. Madrid, Spain
6. Department of Pediatrics, Río Hortega University Hospital, Valladolid, Spain
7. Department of Pediatrics, Basurto University Hospital – Basque Country University, Bilbao, Spain.