Is Ocular Sonography a Reliable Method for the Assessment of Elevated Intracranial Pressure in Children?

Abstract

Point-of-care ultrasound has been widely used by clinicians at the bedside in recent years. Various types of point-of-care ultrasound practices are employed, especially in pediatric emergency rooms and intensive care units. Pediatric intensive care specialists perform point-of-care ultrasound virtually as a part of physical examination since it provides just-in-time vital clinical information, which could assist in acute management strategies in critically ill patients. Measurement of optic nerve sheath diameter using point-of-care ultrasound is a noninvasive and radiation-free technique to determine raised intracranial pressure. Ophthalmic artery and central retinal artery Doppler indices can be used as transcranial Doppler to assess raised intracranial pressure. The aim of this review was to provide detailed information on ultrasonographic measurements of optic nerve sheath diameter and central retinal artery Doppler indices as techniques of interest for predicting increased intracranial pressure in pediatric patients in view of the literature.

A Narrative Review of Point of Care Ultrasound Assessment of the Optic Nerve in Emergency Medicine

“…POCUS of the optic nerve is performed using a high-frequency linear transducer (5–14 MHz) on an ultrasound machine, with a smaller probe footprint providing better sonographic contact with the eye [ 33 , 40 ]. An ocular preset should be used, limiting thermal index to ≤1 and mechanical index to ≤0.23 in accordance with the as low as reasonably achievable (ALARA) principle [ 39 , 41 ].…”

“…Traditionally, ONSD is measured 3 mm behind the globe where the sheath is the most distensible and its measurements are reproducible [ 36 , 40 ]. Though there is recent evidence suggesting no difference in ONSD when measured between 3 and 5 mm posterior to the globe [ 45 ], most studies base their measurements at 3 mm [ 43 ].…”

“…However, the use of doppler must be minimized to avoid ocular injury [ 39 ]. Averaging 2–3 measurements in transverse or sagittal planes may minimize measurement errors [ 40 , 41 ]. Like other ultrasound applications, repeated measurements as clinically indicated may provide additional dynamic information [ 2 ].…”

Optic nerve ultrasound and cardiopulmonary bypass

“…We defined elevated ONSD as greater than 4.0 mm at age <1 year and greater than 4.5 mm at age 1–18 years by referring to previous reports. [ 15 16 17 18 ]…”

“…As an alternative to invasive ICP monitoring, bedside point-of-care ultrasound has been used to measure optic nerve sheath diameter (ONSD) as a surrogate measure of ICP. [ 15 16 17 18 ] The current study measures ONSD during cardiac surgery using CPB in patients with and without single ventricle (Fontan) physiology.…”