1 Department of Anaesthesia, University Hospitals Morecambe Bay Trust, Royal Lancaster Infirmary, Ashton Road, Lancaster LA1 4RP, UK.
2 Department of Anesthesiology and Intensive Care Medicine, Hospitallers Brothers Hospital, Teaching Hospital of the Paracelsus Medical University Salzburg, Austria; ICAR and UIAA MEDCOM, Austria. Electronic address: peter.paal@chello.at.