title: Association between optic nerve sheath diameter and mortality in patients with severe traumatic brain injury.
abstract: OBJECTIVE
  Increased intracranial pressure (ICP) is associated with worse outcomes following traumatic brain injury (TBI). Studies have confirmed that ICP is correlated with optic nerve sheath diameter (ONSD) on ultrasound. The aim of our study was to assess the independent relationship between ONSD measured using CT and mortality in a population of patients admitted with severe TBI.
  
  
  METHODS
  We conducted a retrospective cohort study of patients with a TBI requiring ICP monitoring admitted to the ICU between April 2006 and May 2012 to two neurotrauma centers. ONSD was independently measured by two physicians blinded to patient outcomes. Multivariable logistic regression modeling was used to assess an association between ONSD and hospital mortality.
  
  
  RESULTS
  A total of 220 patients were included in the analysis. Overall, the cohort had a mean age of 35 (SD 17) years and 171 of 220 (79 %) were male. The median admission GCS was 6 (IQR 3-8). Intra-class correlation coefficient between raters for ONSD measurements was 0.92 (95 % CI 0.90-0.94, P < 0.0001). On multivariable analysis, each 1 mm increase in ONSD was associated with a twofold increase in hospital mortality (OR 2.0, 95 % CI 1.2-3.2, P = 0.007). Using linear regression, ONSD was independently associated with increased ICP in the first 48 h after admission (β = 4.4, 95 % CI 2.5-6.3, P < 0.0001).
  
  
  CONCLUSIONS
  In patients with TBI, ONSD measured on CT scanning was independently associated with ICP and mortality.
authors: Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia, Room 2438, Jim Pattison Pavilion, 2nd Floor, 855 West 12th Avenue, Vancouver, BC, V5Z 1M9, Canada, mypindersekhon@gmail.com.
authors: Mypinder S
authors: MS
authors: Sekhon
authors: Paul
authors: P
authors: McBeth
authors: Jie
authors: J
authors: Zou
authors: Lu
authors: L
authors: Qiao
authors: Leif
authors: L
authors: Kolmodin
authors: William R
authors: WR
authors: Henderson
authors: Steve
authors: S
authors: Reynolds
authors: Donald E G
authors: DE
authors: Griesdale
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000401:mortality*; D005260:Female; D015600:Glasgow Coma Scale; D017052:Hospital Mortality; D006801:Humans; D019586:Intracranial Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009186:Myelin Sheath / Q000000981:diagnostic imaging; D009900:Optic Nerve / Q000000981:diagnostic imaging*; D011859:Radiography