Lukas M Löffel1, Dominique Engel2, Patrick Y Wuethrich2. 1. Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. lukas.loeffel@insel.ch. 2. Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.