1. Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
2. Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
3. Center for Advanced Imaging Research, Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Marlene and Stewart Greenebaum, Comprehensive Cancer Center, University of Maryland, Baltimore, MD
4. Department of Emergency Medicine, Inselspital, Bern University Hospital, Bern University, Bern, Switzerland
5. Clinic for Anesthesiology and Intensive Care Medicine, Helios Klinikum Bonn/Rhein-Sieg, Bonn, Germany.