[1] Department of Anaesthesia and Intensive Care,
[2] The Norwegian Radium Hospital,undefined
[3] Montebello,undefined
[4] N-0310 Oslo,undefined
[5] Norway e-mail: u.e.kongsgaard@klinmed.uio.no Tel.: +47-22 93 40 00 Fax: +47-22 93 42 90,undefined
[6] Department of Anaesthesia and Intensive Care,undefined
[7] The Norwegian Radium Hospital,undefined
[8] Montebello,undefined
[9] N-0310 Oslo,undefined
[10] Norway,undefined