1 NIHR Global Health Research Group on Acquired Brain and Spine Injury, University of Cambridge, Cambridge, CB21PZ, UK; Engineering Design Centre, Department of Engineering, University of Cambridge, Cambridge, CB21PZ, UK. Electronic address: bgs30@cam.ac.uk.
2 NIHR Global Health Research Group on Acquired Brain and Spine Injury, University of Cambridge, Cambridge, CB21PZ, UK; Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.
3 NIHR Global Health Research Group on Acquired Brain and Spine Injury, University of Cambridge, Cambridge, CB21PZ, UK; Division of Neurosurgery, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
4 NIHR Global Health Research Group on Acquired Brain and Spine Injury, University of Cambridge, Cambridge, CB21PZ, UK; Engineering Design Centre, Department of Engineering, University of Cambridge, Cambridge, CB21PZ, UK; Division of Anaesthesia, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.