title: Ultrasonographic measured optic nerve sheath diameter as an accurate and quick monitor for changes in intracranial pressure.
abstract: OBJECTIVE
  Ultrasonographic measurement of the optic nerve sheath diameter (ONSD) is known to be an accurate monitor of elevated intracranial pressure (ICP). However, it is yet unknown whether fluctuations in ICP result in direct changes in ONSD. Therefore, the authors researched whether ONSD and ICP simultaneously change during tracheal manipulation in patients in the intensive care unit (ICU) who have suffered a traumatic brain injury (TBI).
  
  
  METHODS
  The authors included 18 ICP-monitored patients who had sustained TBI and were admitted to the ICU. They examined the optic nerve sheath by performing ultrasound before, during, and after tracheal manipulation, which is known to increase ICP. The correlation between ONSD and ICP measurements was determined, and the diagnostic performance of ONSD measurement was tested using receiver operating characteristic curve analysis.
  
  
  RESULTS
  In all patients ICP increased above 20 mm Hg during manipulation of the trachea, and this increase was directly associated with a dilation of the ONSD of > 5.0 mm. After tracheal manipulation stopped, ICP as well as ONSD decreased immediately to baseline levels. The correlation between ICP and ONSD was high (R(2) = 0.80); at a cutoff of ≥ 5.0 mm ONSD, a sensitivity of 94%, a specificity of 98%, and an area under the curve of 0.99 (95% CI 0.97-1.00) for detecting elevated ICP were determined.
  
  
  CONCLUSIONS
  In patients who have sustained a TBI, ultrasonography of the ONSD is an accurate, simple, and rapid measurement for detecting elevated ICP as well as immediate changes in ICP. Therefore, it might be a useful tool to monitor ICP, especially in conditions in which invasive ICP monitoring is not available, such as at trauma scenes.
authors.affiliation: Departments of 1 Anesthesiology.
authors.forename: Iscander M
authors.initials: IM
authors.lastname: Maissan
authors.affiliation: Departments of 1 Anesthesiology.
authors.forename: Perjan J A C
authors.initials: PJ
authors.lastname: Dirven
authors.affiliation: Neurosurgery, and.
authors.forename: Iain K
authors.initials: IK
authors.lastname: Haitsma
authors.affiliation: Departments of 1 Anesthesiology.
authors.forename: Sanne E
authors.initials: SE
authors.lastname: Hoeks
authors.affiliation: Intensive Care, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Diederik
authors.initials: D
authors.lastname: Gommers
authors.affiliation: Departments of 1 Anesthesiology.
authors.forename: Robert Jan
authors.initials: RJ
authors.lastname: Stolker
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D019586:Intracranial Hypertension / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009900:Optic Nerve / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D055815:Young Adult
keywords: ICP = intracranial pressure; ICU = intensive care unit; ONSD; ONSD = optic nerve sheath diameter; TBI = traumatic brain injury; TCD = transcranial Doppler; diagnostic and operative techniques; head trauma; intracranial pressure; neurotrauma; optic nerve sheath; trauma