[1] Spital STS AG, Inst Anaesthesiol, Spitalfacharzt, Thun, Switzerland
[2] Univ East Anglia, Postgrad Student MSc Reg Anaesthesia, Norwich, Norfolk, England
[3] Katholieke Univ Leuven, Sect Anaesthesiol, Dept Cardiovasc Sci, Leuven, Belgium
[4] Univ Hosp Leuven, Leuven, Belgium
[5] Univ Hosp Munster, Dept Anaesthesiol Intens Care & Pain Med, Munster, Germany
[6] Univ Texas Southwestern Med Ctr Dallas, Dept Anaesthesiol & Pain Management, Dallas, TX 75390 USA