1. Department of Anaesthesiology Centre for Anaesthesiological Research Zealand University Hospital Køge Denmark
2. Department of Anaesthesiology Centre of Head and Orthopedics, Rigshospitalet Copenhagen Denmark
3. Department of Anaesthesiology Gentofte Hospital Hellerup Denmark
4. Department of Anaesthesiology Bispebjerg and Frederiksberg Hospital Copenhagen Denmark
5. Department of Clinical Medicine Copenhagen University Copenhagen Denmark