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Regarding “Diagnostic performance of optic nerve sheath diameter for predicting neurologic outcome in post-cardiac arrest patients: A systematic review and meta-analysis”

      To the Editor,
      We recently read with great interest the article by Lee and Jong Yun
      • Lee S.H.
      • Jong Yun S.
      Diagnostic performance of optic nerve sheath diameter for predicting neurologic outcome in post-cardiac arrest patients: a systematic review and meta-analysis.
      entitled “Diagnostic performance of optic nerve sheath diameter for predicting neurologic outcome in post-cardiac arrest patients: A systematic review and meta-analysis” published in the Resuscitation. However, this “systematic review and meta-analysis” incorrectly pooled for one studies.
      • Lee D.H.
      • Lee S.H.
      • Oh J.H.
      • et al.
      Optic nerve sheath diameter measured using early unenhanced brain computed tomography shows no correlation with neurological outcomes in patients undergoing targeted temperature management after cardiac arrest.
      The eligibility criteria of this meta-analysis were availability of sufficient information to reconstruct 2 × 2 contingency tables regarding sensitivity and specificity. However, in the study by Lee et al.
      • Lee D.H.
      • Lee S.H.
      • Oh J.H.
      • et al.
      Optic nerve sheath diameter measured using early unenhanced brain computed tomography shows no correlation with neurological outcomes in patients undergoing targeted temperature management after cardiac arrest.
      , they found that six months after cardiac arrest, good (CPC 1–2) and poor (CPC 3–5) neurological outcomes were observed in 99 and 230 patients, respectively. There was no significant difference in the optic nerve sheath diameter (ONSD) between groups nor between discharged patients who survived and those with hospital mortality. In multivariate logistic analysis, the serum lactate level, age, electrocardiogram (ECG) rhythm in EMS, ECG rhythm in the emergency department, and the absence of the corneal reflex after ROSC were found to be independent predictors for poor neurological outcome. According to the study, the author did not report the cutoff, sensitivity and specificity of ONSD for predict the neurologic outcome in post-cardiac arrest patients. Hence, according to the eligibility criteria and exclusion criteria, this study can not be pooled for analysis.
      The included study by Lee et al.
      • Lee D.H.
      • Lee S.H.
      • Oh J.H.
      • et al.
      Optic nerve sheath diameter measured using early unenhanced brain computed tomography shows no correlation with neurological outcomes in patients undergoing targeted temperature management after cardiac arrest.
      containing 43% of the patients in this meta-analysis, so if excluded may result in an imbalance in prognostic factors associated with the outcome measures that may severely weaken the validity of their results. Therefore, we must caution against the results of the systematic review by Lee et al.

      Conflict of interest statement

      We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript.

      References

        • Lee S.H.
        • Jong Yun S.
        Diagnostic performance of optic nerve sheath diameter for predicting neurologic outcome in post-cardiac arrest patients: a systematic review and meta-analysis.
        Resuscitation. 2019; 138: 59-67
        • Lee D.H.
        • Lee S.H.
        • Oh J.H.
        • et al.
        Optic nerve sheath diameter measured using early unenhanced brain computed tomography shows no correlation with neurological outcomes in patients undergoing targeted temperature management after cardiac arrest.
        Resuscitation. 2018; 128: 144-150

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