1. Department of Pediatric Respiratory Medicine, Hospital CRS El Pino, University of Santiago de Chile (USACH), Santiago, Chile.
2. Department of Pediatrics, Universidade Federal do Pampa (UNIPAMPA), Bagé, Brazil.
3. Hospital Barros Luco, Santiago, Chile.
4. Hospital de San José de la Mariquina, Valdivia, Chile.
5. Hospital del Salvador, Santiago, Chile.
6. Hospital de Chaitén, Chaitén, Chile.