1. Department of Anaesthesiology, University of Oulu, Kajaanintie 52 A, FIN‐90220 Oulu, Finland,
2. Departments of Anaesthesia and Intensive Care, Lapland Central Hospital, PO Box 8041, FIN‐96101 Rovaniemi, Finland,
3. Oulaskangas Hospital, FIN‐86310 Oulainen, Finland,
4. Sairaala Botnia Inc., Kauppurienkatu 27–29, FIN‐90100 Oulu, Finland,
5. Oulu Deaconess Institute, Uusikatu 50, FIN‐90100 Oulu, Finland