1. Department of Anaesthesia; University Children's Hospital; Zurich Switzerland
2. Department of Paediatric Otolaryngology; Great Ormond Street Hospital for Children; London United Kingdom
3. Department of Otorhinolaryngology; University Children's Hospital; Zurich Switzerland
4. Department of Otorhinolaryngology; Sophia Children's Hospital; Erasmus University Medical Centre; Rotterdam The Netherlands
5. Department of Paediatric Pulmonology and Intensive Care Medicine; UKBB; Basel Switzerland
6. Department of Paediatric Pulmonology and Intensive Care Medicine; Dr. von Hauner Children's Hospital; University of Munich; Germany