Optimal timing to measure optic nerve sheath diameter as a prognostic predictor in post-cardiac arrest patients treated with targeted temperature management.

Abstract

We evaluated the optimal timing of optic nerve sheath diameter (ONSD) measurement to predict neurologic outcome in post-cardiac arrest patients treated with target temperature management (TTM). This was a prospective single-centre observational study from April 2018 to March 2019. Good outcome was defined as the Glasgow-Pittsburgh cerebral performance categories (CPC) 1 or 2, and poor outcome as a CPC between 3 and 5. ONSD was measured initially after return of spontaneous circulation (ROSC) (ONSD_initial), at 24 h (ONSD₂₄), 48 h (ONSD₄₈), and 72 h (ONSD₇₂) using ultrasonography. The receiver operating characteristic (ROC) curves and DeLong method were used to compare the values for predicting neurologic outcomes. Out of the 36 patients enrolled, 18 had a good outcome. ONSD₂₄, ONSD₄₈, and ONSD₇₂ were higher in the poor outcome group. The area under ROC curve of ONSD₂₄ was 0.91 (95% confidence interval 0.77-0.98) in predicting poor neurologic outcomes. With a cut off value of 4.90 mm, ONSD₂₄ had a sensitivity of 83.3% and a specificity of 94.4% in predicting poor neurologic outcomes. Our findings demonstrate ONSD₂₄ as a valuable tool to predict the neurologic outcome in post-cardiac arrest patients treated with TTM. Therefore, we recommend performing ONSD measurement using ultrasonography at 24 h after ROSC, rather than immediately after ROSC, to predict neurologic outcome in post-cardiac arrest patients treated with TTM.