Is initial optic nerve sheath diameter prognostic of specific head injury in emergency departments?

BACKGROUND

Emergency departments (EDs) are typically the first medical contact for patients with traumatic brain injury (TBI) and early diagnosis and treatment of intracranial pressure (ICP) in patients with neurotrauma primarily falls under the liability of emergency doctors. Monitoring ICP with optic nerve sheath diameter (ONSD) via tools has gained popularity among emergency service doctors. In this study, we aimed to evaluate the predictive value of ONSD for specific head injury on initial cranial tomography.

METHODS

CT scans of 176 patients with a known intracranial pathology were retrospectively analyzed and compared with normal control CTs of 182 patients presented to ED at the same time interval. The attending radiologist analyzed all initial brain CT scans and randomly sampled control CTs were similarly assessed by the second senior radiologist whom were blind to the patients' medical histories and circumstances of TBI at the time of measurement. ONSD was measured at a distance of 3 mm behind the eyeball, immediately below the sclera.

RESULTS

Right ONSD value was significantly higher in patients with herniation and SAH (p = 0,024 and 0,028, respectively). Left ONSD values was at the level of statistical significance and mean ONSD values was significantly higher in patients with SAH (p = 0.05 and 0.026, respectively). Right-left-mean ONSD values were statistically higher in study group with bilateral lesions on brain CT (p < 0,001). ONSD measurements and patient age were higher in patients who died (p < 0,001).

CONCLUSIONS

ONSD measurement on initial brain CT is lesion dependent and indicates mortality.