title: Individual patient data systematic review and meta-analysis of optic nerve sheath diameter ultrasonography for detecting raised intracranial pressure: protocol of the ONSD research group.
abstract: BACKGROUND
  The purpose of the optic nerve sheath diameter (ONSD) research group project is to establish an individual patient-level database from high quality studies of ONSD ultrasonography for the detection of raised intracranial pressure (ICP), and to perform a systematic review and an individual patient data meta-analysis (IPDMA), which will provide a cutoff value to help physicians making decisions and encourage further research. Previous meta-analyses were able to assess the diagnostic accuracy of ONSD ultrasonography in detecting raised ICP but failed to determine a precise cutoff value. Thus, the ONSD research group was founded to synthesize data from several recent studies on the subject and to provide evidence on the diagnostic accuracy of ONSD ultrasonography in detecting raised ICP.
  
  
  METHODS
  This IPDMA will be conducted in different phases. First, we will systematically search for eligible studies. To be eligible, studies must have compared ONSD ultrasonography to invasive intracranial devices, the current reference standard for diagnosing raised ICP. Subsequently, we will assess the quality of studies included based on the QUADAS-2 tool, and then collect and validate individual patient data. The objectives of the primary analyses will be to assess the diagnostic accuracy of ONSD ultrasonography and to determine a precise cutoff value for detecting raised ICP. Secondly, we will construct a logistic regression model to assess whether patient and study characteristics influence diagnostic accuracy.
  
  
  CONCLUSIONS
  We believe that this IPD MA will provide the most reliable basis for the assessment of diagnostic accuracy of ONSD ultrasonography for detecting raised ICP and to provide a cutoff value. We also hope that the creation of the ONSD research group will encourage further study.
  
  
  BACKGROUND
  PROSPERO registration number: CRD42012003072.
authors.affiliation: Université Claude Bernard Lyon 1, 69003 Lyon, France. julie.dubourg@gmx.fr
authors.forename: Julie
authors.initials: J
authors.lastname: Dubourg
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Messerer
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Karakitsos
authors.forename: Venkatakrishna
authors.initials: V
authors.lastname: Rajajee
authors.forename: Erik
authors.initials: E
authors.lastname: Antonsen
authors.forename: Etienne
authors.initials: E
authors.lastname: Javouhey
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cammarata
authors.forename: Michael
authors.initials: M
authors.lastname: Cotton
authors.forename: Roy Thomas
authors.initials: RT
authors.lastname: Daniel
authors.forename: Carmelo
authors.initials: C
authors.lastname: Denaro
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Douzinas
authors.forename: Clément
authors.initials: C
authors.lastname: Dubost
authors.forename: Moncef
authors.initials: M
authors.lastname: Berhouma
authors.forename: Behrouz
authors.initials: B
authors.lastname: Kassai
authors.forename: Muriel
authors.initials: M
authors.lastname: Rabilloud
authors.forename: Antonino
authors.initials: A
authors.lastname: Gullo
authors.forename: Abderrhammane
authors.initials: A
authors.lastname: Hamlat
authors.forename: Gregorios
authors.initials: G
authors.lastname: Kouraklis
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mannanici
authors.forename: Keith
authors.initials: K
authors.lastname: Marill
authors.forename: Sybille
authors.initials: S
authors.lastname: Merceron
authors.forename: John
authors.initials: J
authors.lastname: Poularas
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ristagno
authors.forename: Vicki
authors.initials: V
authors.lastname: Noble
authors.forename: Sachita
authors.initials: S
authors.lastname: Shah
authors.forename: Heidi
authors.initials: H
authors.lastname: Kimberly
authors.forename: Gianluca
authors.initials: G
authors.lastname: Cammarata
authors.forename: Riccardo
authors.initials: R
authors.lastname: Moretti
authors.forename: Thomas
authors.initials: T
authors.lastname: Geeraerts
mesh_terms: D016208:Databases, Factual; D006801:Humans; D019586:Intracranial Hypertension / Q000000981:diagnostic imaging*; D007427:Intracranial Pressure; D015201:Meta-Analysis as Topic; D009900:Optic Nerve / Q000000981:diagnostic imaging*; D012016:Reference Values; D012107:Research Design; D000078202:Systematic Reviews as Topic; D014463:Ultrasonography
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