1. Department of Anaesthesiology, Intensive Care, Emergency Medicine and Pain Clinic; Turku University Hospital; Turku; Finland
2. Paediatric Research Centre; Tampere University Hospital; Tampere; Finland
3. Department of Neurosurgery; Turku University Hospital; Turku; Finland
4. Department of Surgery; Turku University Hospital; Turku; Finland
5. Department of Otorhinolaryngology; Helsinki University Hospital; Helsinki; Finland
6. Vaasa Central Hospital Administration; Vaasa; Finland
7. Department of Anaesthesiology, Intensive Care, Emergency Medicine and Pain Clinic; Helsinki University Hospital; Helsinki; Finland
8. Hospital District of Southwest Finland Administration; Turku; Finland