1. Department of Pediatrics University of Cincinnati, College of Medicine Cincinnati OH U.S.A.
2. Division of Pulmonary Medicine Cincinnati Children's Hospital Medical Center Cincinnati OH U.S.A.
3. Aerodigestive and Esophageal Center Cincinnati Children's Hospital Medical Center Cincinnati OH U.S.A.
4. Department of Otolaryngology University of Cincinnati, College of Medicine Cincinnati OH U.S.A.
5. Division of Pediatric Otolaryngology Cincinnati Children's Hospital Medical Center Cincinnati OH U.S.A.
6. Department of Pediatrics University of Pittsburgh, School of Medicine Pittsburgh Pennsylvania U.S.A.
7. Division of Pulmonary Medicine Children's Hospital of Pittsburgh Pittsburgh Pennsylvania U.S.A.