Optic Nerve Sheath Diameter Measured by Ultrasonography: How Well Does It Correlate with Intracranial Pressure According to the New Brain Trauma Foundation Guidelines?

Keywords

ONSD - ICP - ultrasound

Introduction: Bedside ultrasonography (USG), measurement of optic nerve sheath diameter (ONSD) has been proposed as a method to detect raised intracranial pressure (ICP) in various clinical settings. We aimed to evaluate the use of USG in the case of intracranial hypertension and find out the cutoff point that predicts ICP accurately at 22 mm Hg.

Methodology/Description: A retrospective analysis of the data collected from a prospective double-blind study performed by performing ocular ultrasounds in 52 adult patients with features of intracranial hypertension was done. The ONSD was measured by USG under anesthesia and compared with the intraventricular ICP measured simultaneously. The optimum cutoff of ONSD to predict ICP > 22 mm Hg was sought.

Results: There was a significant correlation of sonographic ONSD with ICP (r = 0.498, p = 0.000173). An ONSD threshold of 6.3 mm predicted ICP > 22 mm Hg with high sensitivity (89%) and specificity (73%, area under ROC curve = 0.814, p = 0.000424, CI = 0.672–0.956).

Conclusion: Our study confirms the utility of optic nerve ultrasound in the diagnostic evaluation of patients with known or suspected intracranial hypertension. We recommend an ONSD cutoff of 6.3 mm for predicting ICP > 22 mm Hg.

• References

• 1 Dubourg J, Javouhey E, Geeraerts T, Messerer M, Kassai B. Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: a systematic review and meta-analysis.. Intensive Care Med 2011; 37 (07) 1059-1068
• 2 Kristiansson H, Nissborg E, Bartek Jr J, Andresen M, Reinstrup P, Romner B. Measuring elevated intracranial pressure through noninvasive methods: a review of the literature.. J Neurosurg Anesthesiol 2013; 25 (04) 372-385