1. Medical Faculty, Department of Pediatrics and Adolescent Medicine, University Hospital of Cologne, Cologne, Germany
2. Medical Faculty, Division of Pediatric Surgery, University Hospital of Cologne, Cologne, Germany
3. Former Head of Department for Paediatric Anaesthesia, Children's Hospital Cologne, Cologne, Germany
4. Medical Faculty, Experimental Pediatric Pulmonology, University Hospital of Cologne, Cologne, Germany