1 Department of Anaesthesiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland Department of Anesthesia, Northwestern University, Chicago, Illinois Department of Anaesthesiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland Department of Anesthesiology, University of Virginia, Charlottesville, Virginia Department of Anaesthesiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland, markus.luedi2@insel.ch.