English

Abstract

Study objective: The objective of the present study is to determine whether a bedside ultrasonographic measurement of optic nerve sheath diameter and optic fundus examination can accurately predict the computed tomographic (CT) findings of elevated intracranial pressure in adult head injury patients in the emergency department (ED). METHODS: We conducted a prospective, blinded observational study on adult ED patients with suspected intracranial injury with possible elevated intracranial pressure. Exclusion criteria were age younger than 18 years or obvious ocular trauma. All patients underwent fundus examination by a single examiner immediate and after 6 hours of admission. Using a 7.5-MHz ultrasonographic probe on the closed eyelids, a single optic nerve sheath diameter was measured 3 mm behind the globe in each eye. A mean binocular optic nerve sheath diameter greater than 5.00 mm was considered abnormal. Cranial CT findings of shift, edema, or effacement suggestive of elevated intracranial pressure were used to evaluate optic nerve sheath diameter accuracy. RESULTS: 200 patients were studied during the study period of 2 years from 2011-2012. Average age was 38 years, and mean Glasgow Coma Scale score was 9. 22 patients with an optic nerve sheath diameter of 5.6 mm or more had CT findings that correlated with elevated intracranial pressure. The sensitivity for the ultrasonography in detecting elevated intracranial pressure was 100% (95% confidence interval (CI) 68% to 100%) and specificity was 63% (95% CI 50% to 76%). Fundus examination in these 22 patients found to have poor correlation with the CT findings of elevated intracranial pressure with low sensitivity of 64% (95% confidence interval (CI) 56% to 80%) and specificity of only 64% (95% CI 50% to 76%). CONCLUSION: Bedside ED optic nerve sheath diameter ultrasonography has potential as a sensitive screening test for elevated intracranial pressure in adult head injury. However fundus examination was not found to be sensitive screening test in these conditions.