title: Non-invasive Monitoring of Intracranial Pressure Using Transcranial Doppler Ultrasonography: Is It Possible?
abstract: Although intracranial pressure (ICP) is essential to guide management of patients suffering from acute brain diseases, this signal is often neglected outside the neurocritical care environment. This is mainly attributed to the intrinsic risks of the available invasive techniques, which have prevented ICP monitoring in many conditions affecting the intracranial homeostasis, from mild traumatic brain injury to liver encephalopathy. In such scenario, methods for non-invasive monitoring of ICP (nICP) could improve clinical management of these conditions. A review of the literature was performed on PUBMED using the search keywords 'Transcranial Doppler non-invasive intracranial pressure.' Transcranial Doppler (TCD) is a technique primarily aimed at assessing the cerebrovascular dynamics through the cerebral blood flow velocity (FV). Its applicability for nICP assessment emerged from observation that some TCD-derived parameters change during increase of ICP, such as the shape of FV pulse waveform or pulsatility index. Methods were grouped as: based on TCD pulsatility index; aimed at non-invasive estimation of cerebral perfusion pressure and model-based methods. Published studies present with different accuracies, with prediction abilities (AUCs) for detection of ICP ≥20 mmHg ranging from 0.62 to 0.92. This discrepancy could result from inconsistent assessment measures and application in different conditions, from traumatic brain injury to hydrocephalus and stroke. Most of the reports stress a potential advantage of TCD as it provides the possibility to monitor changes of ICP in time. Overall accuracy for TCD-based methods ranges around ±12 mmHg, with a great potential of tracing dynamical changes of ICP in time, particularly those of vasogenic nature.
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Box 167, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK. dac69@cam.ac.uk.
authors.forename: Danilo
authors.initials: D
authors.lastname: Cardim
authors.affiliation: Neurosciences Critical Care Unit, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation, Cambridge, UK.
authors.forename: C
authors.initials: C
authors.lastname: Robba
authors.affiliation: Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Bohdanowicz
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Box 167, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
authors.forename: J
authors.initials: J
authors.lastname: Donnelly
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Box 167, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
authors.forename: B
authors.initials: B
authors.lastname: Cabella
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Box 167, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Box 167, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
authors.forename: M
authors.initials: M
authors.lastname: Cabeleira
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Box 167, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
authors.forename: P
authors.initials: P
authors.lastname: Smielewski
authors.affiliation: Department of Neurology, University Hospital Chemnitz, Chemnitz, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Schmidt
authors.affiliation: Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Box 167, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
authors.forename: M
authors.initials: M
authors.lastname: Czosnyka
mesh_terms: D001927:Brain Diseases / Q000175:diagnosis*; D006801:Humans; D007427:Intracranial Pressure; D064926:Neurophysiological Monitoring / Q000592:standards*; D017585:Ultrasonography, Doppler, Transcranial / Q000592:standards*
keywords: Intracranial pressure; Non-invasive intracranial pressure monitoring; Transcranial Doppler Ultrasonography