title: Optic nerve sheath diameter on computed tomography not predictive of neurological status post-cardiac arrest.
abstract: OBJECTIVE
  Optic nerve sheath diameter (ONSD) measured on a head computed tomography (CT) has been suggested as a potential prognostic factor for poor neurological outcome after cardiac arrest. We performed a single centre retrospective cohort analysis to further investigate this relationship.
  
  
  METHODS
  All patients >18 years of age admitted to St. Paul's Hospital in Vancouver, Canada who survived a cardiac arrest and had a CT scan of the head within 48 hours were included in the analysis.
  
  
  RESULTS
  A total of 72 patients met inclusion criteria for the study; 54 (75.0%) of the patients had a poor neurological outcome, whereas 18 (25.0%) patients were discharged from the hospital with a good outcome. A CT head was obtained for patients in the good outcome group in a mean time of 9.3 hours (SD 10.0) compared to 10.2 hours (SD 11.2) for the poor outcome group (p=0.75). There was no difference in average ONSD observed between the two outcome groups (6.66 mm SD 0.78 v. 6.60 mm SD 0.82, p=0.77). Multiple logistic regression failed to show any association between ONSD and neurological outcome when adjusted for all other covariates (OR 1.32 95% CI 0.40-4.34, p=0.65). Setting an ONSD threshold of >8 mm (OR 2.32, 95% CI 0.14-39.40, p=0.55) or >7 mm (OR 0.28, 95% CI 0.03-2.77, p=0.28) also failed to show any association on neurological outcome.
  
  
  CONCLUSIONS
  There was no observed difference in ONSD between those with a good neurological outcome and those with a poor outcome. ONSD was not an independent predictor of poor neurological outcome.
authors: *Division of Critical Care, Department of Medicine,Vancouver General Hospital,University of British Columbia,Vancouver,BC.
authors: Barret
authors: http://orcid.org/0000-0001-9201-8352
authors: B
authors: Rush
authors: *Division of Critical Care, Department of Medicine,Vancouver General Hospital,University of British Columbia,Vancouver,BC.
authors: Andrew
authors: A
authors: Wormsbecker
authors: *Division of Critical Care, Department of Medicine,Vancouver General Hospital,University of British Columbia,Vancouver,BC.
authors: Landon
authors: L
authors: Berger
authors: *Division of Critical Care, Department of Medicine,Vancouver General Hospital,University of British Columbia,Vancouver,BC.
authors: Katie
authors: K
authors: Wiskar
authors: *Division of Critical Care, Department of Medicine,Vancouver General Hospital,University of British Columbia,Vancouver,BC.
authors: Mypinder S
authors: MS
authors: Sekhon
authors: *Division of Critical Care, Department of Medicine,Vancouver General Hospital,University of British Columbia,Vancouver,BC.
authors: Donald E
authors: DE
authors: Griesdale
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001927:Brain Diseases / Q000175:diagnosis* / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006323:Heart Arrest / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D059906:Neuroimaging / Q000379:methods; D009483:Neuropsychological Tests; D009900:Optic Nerve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D017741:Survivors; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: cardiac arrest; optic nerve sheath diameter; prognosis