1 Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
2 Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
3 Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. Electronic address: werner.zgraggen@insel.ch.