Prognostic significance of optic nerve sheath diameter on computed tomography scan with severity of blunt traumatic brain injury in the emergency department.

Optic nerve sheath diameter measurement (ONSD) has been associated with identifying the prognosis of traumatic brain injury (TBI) patients. The study was planned to evaluate the prognostic value of ONSD measured on the initial brain computed tomography (CT) scan performed on patients with blunt TBI in the emergency department(ED). This retrospective cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, and comprised data of moderate and severe TBI patients from January to December 2014. ONSD for each eye on the initial CT scan and Glasgow Coma Scale (GCS) was measured upon patient presentation. Correlation between presentation GCS and ONSD was done through Pearson's correlation. Receiver operator curve (ROC) analysis was done to measure the predictive values of ONSD for mortality. Of the 276 patients, 211(76%) were males and 65(23%) females. ONSD was measured on 160(58%) patients. The mean ONSD measured on CT scan was 3.8±1. The Pearson's correlation between the severity of brain injury as per GCS at presentation and ONSD was not significant (-0.182). We concluded that ONSD measured on the initial CT brain scan had good association with the severity of blunt TBI in patients presenting to the ED.