title: Noninvasive Intracranial Pressure Determination in Patients with Subarachnoid Hemorrhage.
abstract: Intracranial pressure (ICP) should ideally be measured in many conditions affecting the brain. The invasiveness and associated risks of the measurement modalities in current clinical practice restrict ICP monitoring to a small subset of patients whose diagnosis and treatment could benefit from ICP measurement. To expand validation of a previously proposed model-based approach to continuous, noninvasive, calibration-free, and patient-specific estimation of ICP to patients with subarachnoid hemorrhage (SAH), we made waveform recordings of cerebral blood flow velocity in several major cerebral arteries during routine, clinically indicated transcranial Doppler examinations for vasospasm, along with time-locked waveform recordings of radial artery blood pressure (APB), and ICP was measured via an intraventricular drain catheter. We also recorded the locations to which ICP and ABP were calibrated, to account for a possible hydrostatic pressure difference between measured ABP and the ABP value at a major cerebral vessel. We analyzed 21 data records from five patients and were able to identify 28 data windows from the middle cerebral artery that were of sufficient data quality for the ICP estimation approach. Across these windows, we obtained a mean estimation error of -0.7 mmHg and a standard deviation of the error of 4.0 mmHg. Our estimates show a low bias and reduced variability compared with those we have reported before.
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA.
authors.forename: James
authors.initials: J
authors.lastname: Noraky
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Building 10, Room 140K, 77 Massachusetts Avenue, Cambridge, MA, USA.
authors.forename: George C
authors.initials: GC
authors.lastname: Verghese
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Searls
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: Vasileios A
authors.initials: VA
authors.lastname: Lioutas
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: Shruti
authors.initials: S
authors.lastname: Sonni
authors.affiliation: Division of Neurosurgery, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: Ajith
authors.initials: A
authors.lastname: Thomas
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Building E25, Room 324, 77 Massachusetts Avenue, Cambridge, MA, USA. thomas@mit.edu.|Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA, USA. thomas@mit.edu.
authors.forename: Thomas
authors.initials: T
authors.lastname: Heldt
mesh_terms: D001783:Blood Flow Velocity; D001794:Blood Pressure; D002552:Cerebral Ventricles; D002560:Cerebrovascular Circulation; D004322:Drainage; D005260:Female; D006801:Humans; D019586:Intracranial Hypertension / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000209:etiology; D007427:Intracranial Pressure; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D008991:Monitoring, Physiologic; D017534:Radial Artery; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000503:physiopathology*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging* / Q000209:etiology
keywords: Brain injury; Intracranial pressure; Model-based patient monitoring; Noninvasive estimation; Subarachnoid hemorrhage