Relationship of Optic Nerve Sheath Diameter and Intracranial Hypertension in Patients with Traumatic Brain Injury.

BACKGROUND: to study the association between optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in patients with moderate-to-severe brain injury. PATIENTS AND METHODS: A retrospective cohort study of traumatic brain injury (TBI) patients was conducted between 2010 and 2014. Data were analyzed and compared according to the ICP monitoring cutoff values. Outcomes included intracranial hypertension (ICH) and mortality. RESULTS: A total of 167 patients with a mean age of 33 ± 14 years, of them 96 had ICP monitored. ICP values correlated with ONSD measurement (r = 0.21, P = 0.04). Patients who developed ICH were more likely to have higher mean ONSD (P = 0.01) and subarachnoid hemorrhage (SAH) (P = 0.004). Receiver operating curve for ONSD showed a cutoff value of 5.6 mm to detect ICH with sensitivity 72.2% and specificity 50%. Age and ICP were independent predictors of inhospital mortality in multivariate model. Another model with same covariates showed ONSD and SAH to be independent predictors of ICH. Simple linear regression showed a significant association of ONSD with increased ICP (ß = 0.21, 95% confidence interval 0.25-5.08, P = 0.03). CONCLUSIONS: ONSD is a simple noninvasive measurement on initial CT in patients with TBI that could be a surrogate for ICP monitoring. However, further studies are warranted.