title: Cerebral haemodynamics during experimental intracranial hypertension.
abstract: Intracranial hypertension is a common final pathway in many acute neurological conditions. However, the cerebral haemodynamic response to acute intracranial hypertension is poorly understood. We assessed cerebral haemodynamics (arterial blood pressure, intracranial pressure, laser Doppler flowmetry, basilar artery Doppler flow velocity, and vascular wall tension) in 27 basilar artery-dependent rabbits during experimental (artificial CSF infusion) intracranial hypertension. From baseline (∼9 mmHg; SE 1.5) to moderate intracranial pressure (∼41 mmHg; SE 2.2), mean flow velocity remained unchanged (47 to 45 cm/s; p = 0.38), arterial blood pressure increased (88.8 to 94.2 mmHg; p < 0.01), whereas laser Doppler flowmetry and wall tension decreased (laser Doppler flowmetry 100 to 39.1% p < 0.001; wall tension 19.3 to 9.8 mmHg, p < 0.001). From moderate to high intracranial pressure (∼75 mmHg; SE 3.7), both mean flow velocity and laser Doppler flowmetry decreased (45 to 31.3 cm/s p < 0.001, laser Doppler flowmetry 39.1 to 13.3%, p < 0.001), arterial blood pressure increased still further (94.2 to 114.5 mmHg; p < 0.001), while wall tension was unchanged (9.7 to 9.6 mmHg; p = 0.35).This animal model of acute intracranial hypertension demonstrated two intracranial pressure-dependent cerebroprotective mechanisms: with moderate increases in intracranial pressure, wall tension decreased, and arterial blood pressure increased, while with severe increases in intracranial pressure, an arterial blood pressure increase predominated. Clinical monitoring of such phenomena could help individualise the management of neurocritical patients.
authors.affiliation: 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
authors.forename: Joseph
authors.initials: J
authors.lastname: Donnelly
authors.affiliation: 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.|2 Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
authors.affiliation: 3 Queen Elizabeth Hospital, Birmingham, UK.
authors.forename: Spencer
authors.initials: S
authors.lastname: Harland
authors.affiliation: 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
authors.forename: Georgios V
authors.initials: GV
authors.lastname: Varsos
authors.affiliation: 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
authors.forename: Danilo
authors.initials: D
authors.lastname: Cardim
authors.affiliation: 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
authors.forename: Chiara
authors.initials: C
authors.lastname: Robba
authors.affiliation: 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Liu
authors.affiliation: 4 Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, British Columbia, Canada.
authors.forename: Philip N
authors.initials: PN
authors.lastname: Ainslie
authors.affiliation: 1 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Smielewski
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation; D005260:Female; D006439:Hemodynamics; D019586:Intracranial Hypertension / Q000097:blood* / Q000000981:diagnostic imaging; D007427:Intracranial Pressure; D008297:Male; D011817:Rabbits; D017585:Ultrasonography, Doppler, Transcranial
keywords: Intracranial hypertension; cerebral blood flow; cerebral haemodynamics; intracranial pressure; pressure reactivity; vascular function