title: Change in Pulsatile Cerebral Arterial Pressure and Flow Waves as a Therapeutic Strategy?
abstract: While intracranial pressure (ICP), arterial pressure and transcranial middle cerebral artery flow velocity (MCAFV) are often monitored in unconscious patients following stroke or head injury, the value of waveform indices has not been fully established. We retrospectively analysed the data of eight adults (aged 19-36 years) with closed head injury who had spontaneous and repeated episodes of elevated ICP (i.e. "plateau waves"). MCAFV was measured using transcranial Doppler, ICP using a Codman catheter and radial artery pressure using cannulation. Ascending aortic pressure (AAP) was generated from the radial artery using SphygmoCor(TM). Cerebral perfusion pressure (CPP) was calculated as AAP - ICP in the time domain.During the period of increased ICP, ICP and cerebral flow velocity amplitude increased significantly compared with the basal condition, while cerebral mean flow decreased. Amplitude of the secondary peak in ICP, AAP and MCAFV waveform became apparent.An increase in the amplitude of ICP, AAP and MCAFV waves can be attributed to the greater prominence of reflected waves from the lower body, which was apparent in pulse waveform analysis. Arterial vasodilators such as nitrates reduce reflected pressure waves from the lower body and, by decreasing the amplitude of AAP, ICP and MCAFV, may be as beneficial for the cerebral circulation as they are for the left ventricle of the heart.
authors.affiliation: Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia.
authors.forename: Mi Ok
authors.initials: MO
authors.lastname: Kim
authors.affiliation: Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia.|St Vincent's Clinic, Suite 810, 438 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia.
authors.forename: Audrey
authors.initials: A
authors.lastname: Adji
authors.affiliation: St Vincent's Clinic, Suite 810, 438 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia. m.orourke@unsw.edu.au.|University of New South Wales/VCCRI, Sydney, NSW, Australia. m.orourke@unsw.edu.au.
authors.forename: Michael F
authors.initials: MF
authors.lastname: O'Rourke
authors.affiliation: Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia.
authors.forename: Alberto P
authors.initials: AP
authors.lastname: Avolio
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Smielewski
authors.affiliation: Academic Neurosurgical Unit, Addenbrooke's Hospital, Cambridge University, Cambridge, UK.
authors.forename: John D
authors.initials: JD
authors.lastname: Pickard
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D000070642:Brain Injuries, Traumatic / Q000150:complications / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D019586:Intracranial Hypertension / Q000209:etiology / Q000503:physiopathology*; D007427:Intracranial Pressure / Q000502:physiology; D008297:Male; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011673:Pulsatile Flow / Q000502:physiology*; D063177:Pulse Wave Analysis; D012189:Retrospective Studies; D017585:Ultrasonography, Doppler, Transcranial; D014665:Vasodilator Agents / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D014665:Vasodilator Agents
keywords: Central aortic pressure pulse; Intracranial pressure; Pressure wave reflection; Waveform analysis