Value of ratio of optic nerve sheath diameter to eyeball transverse diameter in assessing intracranial pressure in patients with brain injury: measurement using ultrasound

Objective To evaluate the value of the ratio of optic nerve sheath diameter to eyeball transverse diameter (ONSD/ETD) in assessing intracranial pressure using ultrasound in the patients with brain injury. Methods Forty-six patients of both sexes with brain injury in the surgical intensive care unit, were selected.Craniotomy was performed within 24 h after admission to hospital, and the intracranial pressure probe was placed in the lateral cerebral ventricle of the enrolled patients who were aged 18-80 yr, with Glasgow Coma Scale score 3-15.ONSD and ETD were measured within 3 days after operation, three times a day, and the intracranial pressure was simultaneously recorded.The correlation between ONSD/ETD ratio and intracranial pressure were analyzed using the Pearson correlation analysis.The receiver operating characteristic curve was used to evaluate the accuracy of ONSD/ETD ratio in assessing the intracranial hypertension (intracranial pressure>20 mmHg). Results The ONSD/ETD ratio was positively correlated with intracranial pressure (r=0.720, P<0.01). The area under the receiver operating characteristic curve was 0.900 (95% confidence interval 0.854-0.946), and the threshold was 0.248 (sensitivity 89.4%, specificity 77.5%). Conclusion The ONSD/ETD ratio produces higher accuracy in assessing intracranial pressure in the patients with brain injury. Key words: Optic nerve; Eye; Intracranial hypertension; Craniocerebral trauma