Patrick Schoettker1, Sina Grape2. 1. Department of Anesthesiology, University Hospital Center, University of Lausanne, Rue du Bugnon 46, 1011, Lausanne, Switzerland. Patrick.Schoettker@chuv.ch. 2. Department of Anesthesiology, Hôpital de Sion, CH-1950, Sion, Switzerland.