Abstract
BackgroundUltrasonograpic retrobulbar optic nerve sheath diameter (ONSD) measurement is considered to be an alternative noninvasive method to estimate intracranial pressure,but the further validation is urgently needed. The aim of the current study was to investigate the association of the ultrasonographic ONSD and intracranial pressure (ICP) in patients.MethodsOne hundred and ten patients whose intracranial pressure measured via lumbar puncture were enrolled in the study. Their retrobulbar ONSD with B-scan ultrasound was determined just before lumber puncture. The correlation between the ICP and the body mass index (BMI), ONSD or age was established respectively with the Pearson correlation coefficient analysis. The discriminant analysis was used to obtain a discriminant formula for predicting ICP with the ONSD、BMI、gender and age. Another 20 patients were recruited for further validation the efficiency of this discriminant equation.ResultsThe mean ICP was 215.3 ± 81.2 mmH2O. ONSD was 5.70 ± 0.80 mm in the right eye and 5.80 ± 0.77 mm in the left eye. A significant correlation was found between ICP and BMI (r = 0.554, p < 0.001), the mean ONSD (r = 0.61, P < 0.001), but not with age (r = −0.131, p = 0.174) and gender (r = 0.03, p = 0.753). Using receiver operating characteristic (ROC) curve analysis, the critical value for the risk mean-ONSD was 5.6 mm from the ROC curve, with the sensitivity of 86.2% and specificity of 73.1%. With 200 mmH2O as the cutoff point for a high or low ICP, stepwise discriminant was applied, the sensitivity and specificity of ONSD predicting ICP was 84.5%-85.7% and 86.5%-92.3%.ConclusionsOphthalmic ultrasound measurement of ONSD may be a good surrogate of invasive ICP measurement. This non-invasive method may be an alternative approach to predict the ICP value of patients whose ICP measurement via lumbar puncture are in high risk. The discriminant formula, which incorporated the factor of BMI, had similar sensitivity and higher specificity than the ROC curve.
Highlights
Ultrasonograpic retrobulbar optic nerve sheath diameter (ONSD) measurement is considered to be an alternative noninvasive method to estimate intracranial pressure,but the further validation is urgently needed
intracranial pressure (ICP) was significantly associated with the mean ONSD (r = 0.61, P < 0.001) (Fig. 3a) or body mass index (BMI) (r = 0.55, p < 0.001) (Fig. 3b), but not associated with age (r = −0.131, P = 0.174) (Fig. 3c) or gender (r = 0.03, P = 0.753) (Fig. 3d)
In our study, we found that ICP was significantly associated with the mean ONSD (r = 0.61, P < 0.001) and BMI (r = 0.55, p < 0.001)
Summary
Ultrasonograpic retrobulbar optic nerve sheath diameter (ONSD) measurement is considered to be an alternative noninvasive method to estimate intracranial pressure,but the further validation is urgently needed. The aim of the current study was to investigate the association of the ultrasonographic ONSD and intracranial pressure (ICP) in patients. Intracranial hypertension is a critical life-threatening condition caused by a variety of neurological and nonneurological diseases. It is a sign of poor prognosis including risk of death from brainstem herniation [1]. A direct and invasive measurement via lumbar puncture is commonly used for ICP measurement clinically [3, 4]. Potential risks such as hemorrhage, infection, and brainstem herniation with this invasive measurement of ICP are greatly concerned [5]. It is not feasible to conduct on the patients who are too young or with contraindication such as coagulopathy, puncture area skin infection and thrombocythemia [6]
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