The rapid recognition and timely treatment of elevated ICP is of paramount importance so that it could reduce morbidity and mortality, as well as improve patients’ outcome. This study is trying to evaluate the diagnostic accuracy of sonographic optic nerve sheath diameter (ONSD) in detection of EICP.
Methods: Sonographic ONSD of patients with head trauma suspicious for EICP were evaluated by a trained resident of emergency medicine, who was blind to the clinical and brain computed tomography scan (CT) findings of patients. Immediately after ultrasonography, CT was performed and reported by an expert radiologist without awareness from other results of the patients. Finally, ultrasonographic and BCT findings regarding EICP were compared. To evaluate the ability of sonographic ONSD in predicting the BCT findings, receiver operating characteristic (ROC) curve were used. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) of sonographic ONSD in determining of EICP was calculated. P<0.05 was considered to be statistically significant.
Results: There were 260 patients (84% male), with mean age of 41.2 + 15.4 years. BCT showed signs of EICP, in 200 cases (76.92%). The means of the ONSD in the patients with EICP and normal ICP were 5.43 + 0.55 and 4.75 + 0.55 mm, respectively (P<0.01). Sensitivity, specificity, PPV, NPV, PLR, and NLR of ONSD for prediction of EICP were 94.34%, 93.75%, 98.52%, 78.52%, 13.42, and 0.06, respectively.
Conclusion: Sonographic diameter of optic nerve sheath could be considered as an available, accurate, and noninvasive screening tool in determining the elevated intracranial pressure in cases with head trauma.