[1] Univ Groningen Hosp, Dept Surg, NL-9700 RB Groningen, Netherlands
[2] Leiden Univ, Med Ctr, Dept Surg, Leiden, Netherlands
[3] Univ Bologna, S Orsola M Malpighi Hosp, Dept Anesthesiol, Bologna, Italy
[4] Univ Hosp Dijkzigt, Dept Anesthesiol, NL-3015 GD Rotterdam, Netherlands
[5] Huddinge Univ Hosp, Dept Anesthesiol, Huddinge, Sweden
[6] Helsinki Univ Hosp, Dept Anesthesiol, FIN-00170 Helsinki, Finland
[7] Univ Hosp Dijkzigt, Dept Med, NL-3015 GD Rotterdam, Netherlands