1. Department of Neurosurgery, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
2. Department of Neurosurgery, Institution of Clinical Science in Lund, Lund University Hospital, and Lund University, Lund, Sweden.
3. Department of Anesthesia and Intensive Care, Institution of Clinical Science in Lund, Lund University Hospital, and Lund University, Lund, Sweden.