Ultrasound of optic nerve sheath diameter for monitoring intracranial pressure

Abstract

Introduction: Noninvasive neuromonitoring in critically ill patients is a first-line option for the management of fatal complications derived from increased intracranial pressure. This modality includes ultrasound of optic nerve sheath diameter, which is a quick technique, easy to perform and available at the bedside.

Objectives: To describe significant and state-of-the-art aspects regarding the use of ultrasound for monitoring intracranial pressure through measurement of the optic nerve sheath diameter in different neuroclinical settings.

Methods: A review was carried out, between May and July 2020, of the literature published in databases such as PubMed/Medline, SciELO and Google Scholar. Publications in English and Spanish were reviewed. Forty-six bibliographic sources were chosen, as long as they met the inclusion criteria. Fundamental aspects are described, such as the ultrasound anatomy of the optic nerve, the technique procedures and its use in neurocritical entities such as head trauma, stroke and brain death, among others.

Conclusions: Ultrasound of the optic nerve sheath is a widely accepted noninvasive choice for measurement of increased intracranial pressure. With a diameter of 5.0 to 5.9 mm or more, the diagnosis of intracranial hypertension can be assumed with high sensitivity and specificity, although its use should be individualized in each neurocritical pathology. The learning curve for carrying out the procedure is short and satisfies the necessary skills.

Keywords: intracranial pressure; ultrasound; optic nerve sheath diameter; noninvasive neuromonitoring.