1. Department of Anesthesia Centre of Head and Orthopedics, Rigshospitalet, University of Copenhagen Copenhagen Denmark
2. Department of Clinical Medicine University of Copenhagen Copenhagen Denmark
3. Department of Clinical Epidemiology Aarhus University Hospital Aarhus Denmark
4. Department of Anesthesia Herlev Hospital Herlev Denmark
5. Danish Cholinesterase Research Unit, Department of Anesthesia Herlev Hospital Herlev Denmark
6. Danish Ministry of Defence Personnel Agency Copenhagen Denmark