title: Sonographic Optic Nerve Sheath Diameter: A Simple and Rapid Tool to Assess the Neurologic Prognosis After Cardiac Arrest.
abstract: OBJECTIVE
  The early prediction of hypoxic encephalopathy after cardiac arrest is challenging. Measurement of the optic nerve sheath diameter (ONSD) by using sonography is a straightforward, noninvasive technique to detect an increased intracranial pressure, which can even be conducted at the bedside. However, it remains unknown whether or not sonographic ONSD measurement is valuable as a prognostic indicator of hypoxic encephalopathy.
  
  
  METHODS
  Seventeen patients after cardiac arrest were retrospectively enrolled in this study. ONSD measurements 3 mm behind the papilla were recorded. A Glasgow Outcome Scale score of 4 or above was considered to indicate a favorable prognosis.
  
  
  RESULTS
  The mean ONSD associated with a favorable prognosis was 5.0 mm (4.4-6.1 mm). The ONSD associated with a poor prognosis was 6.1 mm (5.4-7.2 mm). ONSD less than or equal to 5.4 mm was an indicator of a favorable prognosis, with a sensitivity of 83%, specificity of 73%, positive likelihood ratio of 3.1, and negative likelihood ratio of .23.
  
  
  CONCLUSIONS
  Sonographic ONSD measurement is a simple, rapid technique to assess the neurological prognosis after cardiac arrest.
authors.affiliation: Rakuwakai Marutamachi Hospital, Emergency and General Internal Medicine, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ueda
authors.affiliation: Rakuwakai Marutamachi Hospital, Emergency and General Internal Medicine, Kyoto, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Ishida
authors.affiliation: Rakuwakai Marutamachi Hospital, Emergency and General Internal Medicine, Kyoto, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kojima
authors.affiliation: Rakuwakai Marutamachi Hospital, Emergency and General Internal Medicine, Kyoto, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yoshikawa
authors.affiliation: Rakuwakai Marutamachi Hospital, Emergency and General Internal Medicine, Kyoto, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yonemoto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006323:Heart Arrest / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D002534:Hypoxia, Brain / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009900:Optic Nerve / Q000000981:diagnostic imaging*; D011379:Prognosis; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*
keywords: Ultrasonography; cardiac arrest; hypoxic encephalopathy; optic nerve sheath diameter; prognosis