[1] Aarhus Univ Hosp, Dept Anaesthesia & Intens Care Med, DK-8000 Aarhus C, Denmark
[2] Aarhus Univ Hosp, Ctr Psychiat Res, Risskov, Denmark
[3] Aarhus Univ, Dept Biostat, Aarhus C, Denmark
[4] Hillerod Hosp, Anaesthesia & Intens Care Med, Hillerod, Denmark
[5] Univ Copenhagen, Rigshosp, Univ Hosp Ctr Nursing & Care Res, Fac Hlth Sci,UCSF,Copenhagen Univ Hosp, DK-2100 Copenhagen O, Denmark