1. Department of Peadiatrics; School of Medicine; Universidad Nacional de Colombia; Bogota Colombia
2. Department of Peadiatric Pulmonology and Peadiatric Critical Care Medicine; School of Medicine; Universidad El Bosque; Bogota Colombia
3. Research Unit; Military Hospital of Colombia; Bogota Colombia
4. Departments of Peadiatrics and Family Medicine; School of Medicine; Pontificia Universidad Católica de Chile; Santiago Chile