1 Department of Anesthesiology and Intensive Care Medicine, Zealand University Hospital, University of Copenhagen, Copenhagen, Denmark Division of Clinical and Functional Anatomy, Medical University of Innsbruck, Innsbruck, Austria Department of Anesthesiology and Intensive Care Medicine, Aarhus University Hospital, Aarhus, Denmark Department of Anesthesiology and Intensive Care Medicine, Zealand University Hospital, University of Copenhagen, Copenhagen, Denmark, jens.borglum@gmail.com.