[1] Univ Tampere, Sch Med, FIN-33101 Tampere, Finland
[2] Tampere Univ Hosp, Crit Care Med Res Grp, Dept Intens Care Med, Tampere, Finland
[3] Tampere Univ Hosp, Dept Surg & Anaesthesia, Tampere, Finland
[4] Helsinki Univ Hosp, Dept Anaesthesia & Intens Care, Helsinki, Finland