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

Aims: We evaluated the diagnostic performance of optic nerve sheath diameter (ONSD) for prediction of neurologic outcome in post-cardiac arrest patients and relative prediction performance according to ONSD measurement modality. Data sources: PubMed and EMBASE databases were searched for diagnostic accuracy studies that used ocular ultrasound or brain computed tomography (CT) for prediction of neurologic outcome. Bivariate modelling and hierarchical-summary and receiver-operating-characteristic modelling were performed to evaluate diagnostic performance. A pooled diagnostic odds ratio with a 95% confidence interval not including 1 was considered informative. Subgroup analysis was performed according to the modality (ocular US vs. brain CT). Methodologic quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies−2 tool. We performed meta-regression analyses for heterogeneity exploration. Results: Eight studies including 766 patients were included. For prediction of poor neurologic outcome, ONSD showed pooled sensitivity 0.41, pooled specificity 0.99, and area under the receiver-operating-characteristic curve 0.86. According to the pooled diagnostic odds ratios, ONSD was informative for prediction of neurologic outcome. In subgroup analysis, ONSD on ocular ultrasound showed significantly higher sensitivity and similar specificity than that on brain CT. On meta-regression analysis, locale, time to examination after return of spontaneous circulation, cause of cardiac arrest, and reference standard were sources of heterogeneity. Conclusion: ONSD may be useful for predicting neurologic outcomes in post-cardiac arrest patients. Measuring the ONSD specifically using ocular ultrasound, application in patients with cardiac-origin cardiac arrest, and using the Glasgow-Pittsburgh Cerebral Performance Categories for neurologic outcome evaluation are recommended for more accurately predicting neurologic outcomes.