title: Noninvasive Assessment of ICP: Evaluation of New TBI Data.
abstract: In a previously introduced mathematical model, intracranial pressure (ICP) was noninvasively assessed using cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP). In this study this method is evaluated using new data from patients with traumatic brain injury (TBI).
  
  
  
  Three hundred fifteen data recordings of 137 patients (114 men; age 14-78 years, mean age 37 ± 17 years) with severe TBI were studied. CBFV, ABP, and invasively assessed ICP were simultaneously recorded for 1 h. Noninvasive ICP (nICP) was calculated and compared with ICP.
  
  
  
  On 315 recordings, average deviation between ICP and nICP (± standard deviation) was 4.9 ± 3.3 mmHg. The standard deviation of differences (ICP - nICP) was 5.6 mmHg. The 95 % confidence interval of ICP prediction ranged from -9.6 to 12.3 mmHg. Mean ICP was 16.7 mmHg and mean nICP was 18.0 mmHg. When nICP was adjusted by their difference 1.3 mmHg (nICPadj = nICP - 1.3), the 95 % confidence limits of ICP prediction became ±11.0 mmHg. In recordings with highly dynamic ICP signals (n = 27), ICP and nICP correlated on average with R = 0.51 ± 0.47.
  
  
  
  nICP assessment showed reasonable accuracy and may be used in clinical studies of patients without any indication for ICP probe implantation.
authors.affiliation: Department of Neurology, Medical Centre Chemnitz, Dresdner Str. 178, 09131, Chemnitz, Germany. B.Schmidt@skc.de.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
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: Department of Neurology, Medical Centre Chemnitz, Dresdner Str. 178, 09131, Chemnitz, Germany.
authors.forename: Ronny
authors.initials: R
authors.lastname: Plontke
authors.affiliation: Department of Neurology, Medical Centre Chemnitz, Dresdner Str. 178, 09131, Chemnitz, Germany.
authors.forename: Jens J
authors.initials: JJ
authors.lastname: Schwarze
authors.affiliation: Department of Neurology, Medical Centre Chemnitz, Dresdner Str. 178, 09131, Chemnitz, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Klingelhöfer
authors.affiliation: Department of Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK.
authors.forename: John D
authors.initials: JD
authors.lastname: Pickard
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D000070642:Brain Injuries, Traumatic / Q000150:complications / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; 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; D015599:Trauma Severity Indices; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*; D055815:Young Adult
keywords: Arterial blood pressure; Cerebral blood flow; Intracranial pressure; Transcranial Doppler ultrasonography