1. Department of Neurosurgery, Royal Perth Hospital, Perth, Western Australia, Australia
2. Department of Neurosurgery, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
3. Department of Medical Engineering and Physics, Royal Perth Hospital, Perth, Western Australia, Australia
4. Department of Intensive Care, Royal Perth Hospital and School of Population Health, University of Western Australia, Perth, Western Australia, Australia
5. Department of Neurosurgery, Sir Charles Gairdner Hospital and Department of Neurosurgery, Royal Perth Hospital, Perth, Western Australia, Australia