Ultrasound-Measured Optic Nerve Sheath Diameter Predicts Cognitive Dysfunction After Resuscitation: A Retrospective Study

Summary

This retrospective observational study evaluated optic nerve sheath diameter (ONSD) as a predictor of cognitive dysfunction in post-resuscitation neurological ICU patients. Persistently elevated ONSD values were associated with poor neurological outcomes, supporting its role as a rapid and non-invasive prognostic tool.

Abstract

Optic nerve sheath diameter (ONSD) measured by bedside ultrasonography has emerged as a promising non-invasive surrogate marker of intracranial pressure and may have prognostic value in post-resuscitation patients. This retrospective observational study evaluated the utility of ONSD in predicting cognitive dysfunction among neurological intensive care unit (ICU) patients following cardiac arrest. A total of 60 adult patients who achieved return of spontaneous circulation (ROSC) were initially identified, of whom 48 patients with complete follow-up data were included in the final analysis. Serial ONSD measurements were obtained at baseline (within 6 h post-ROSC), 24 h, and 72 h using standardized transorbital ultrasound techniques. Neurological status was assessed using the Glasgow Coma Scale (GCS), and cognitive outcomes were evaluated using the mini-mental state examination (MMSE) and the Montreal cognitive assessment (MoCA) after recovery of consciousness. Patients with favorable neurological outcomes demonstrated significantly lower baseline ONSD values and a progressive decline over time, which correlated with improvement in GCS scores. In contrast, persistently elevated ONSD values were associated with poor cognitive outcomes, minimal neurological recovery, and higher early mortality. Receiver operating characteristic analysis identified an ONSD cutoff value of 5.8 mm for predicting poor outcomes, with a sensitivity of 42.9% and specificity of 85.9%. These findings suggest that serial ONSD measurements are a rapid, reproducible, and non-invasive bedside tool that may aid early neurological prognostication following cardiac arrest. Integration of ONSD with clinical parameters may enhance risk stratification in critical care settings.

Introduction

Cardiac arrest (CA) is one of the main causes of mortality and long-term neurological disability in the world, and survivors often have post-resuscitation brain injury that is defined by cognitive impairments, encephalopathy, and lack of functional recovery^1,2. Timely detection of patients at risk of adverse neurological outcomes is necessary in the right direction to inform therapeutic interventions, prognostic counseling, and intensive care resources. Nevertheless, prognostic tools currently in use, such as the neurological examination, serum biomarkers, such as neuron-specific enolase, and neuroimaging, suc....

Protocol

Retrieved records of adult patients admitted to the neurological intensive care unit (ICU) following cardiac arrest over a defined 12-month period. Confirmed that all patients had achieved return of spontaneous circulation (ROSC). This study was approved by the Ethics Committee of The Third Hospital of Wuhan (No.: KY2025-044). Consent requirements were waived for retrospective data collection in accordance with the Declaration of Helsinki and good clinical practice guidelines.

1. Inclusion and exclusion criteria

1. Include adult patients aged ≥18 years who achieved return of spontaneous circulation (ROSC) fol....

Results

A total of 60 patients were enrolled in the study as per the available database. Of these, 48 completed full follow-up and were included in the final analysis. While 12 were excluded due to incomplete follow-up or poor ultrasound visualization. The mean age of participants was 56.4 ± 10.7 years, with a male-to-female ratio of 1.8:1.

Positive outcomes
In patients who demonstrated good neurological recovery (defined as regaining full consciousness with mini-mental state exam.......

Discussion

This paper reveals that measurement of optic nerve sheath diameter (ONSD) by means of ultrasound is a viable, fast, and non-invasive method of predicting cognitive impairment in post-resuscitation ICU patients. Continuous high ONSD levels corresponded with unfavorable neurological and cognitive results, and declining tendencies were linked with recovery, indicating that it can be utilized as a surrogate endpoint of intracranial pressure (ICP). The results are consistent with the findings of earlier studies which indicate.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Portable Ultrasound System	Mindray Medical International Co., Ltd.	M9 or TE7 series	Used for bedside ultrasonographic measurement of ONSD in ICU settings. Compact and high-resolution imaging capability.
High-frequency Linear Probe (7.5–13 MHz)	Mindray / Philips / GE Healthcare	e.g., L12-4 (Philips), L10-5 (Mindray), or ML6-15 (GE)	Required for precise visualization of the optic nerve and sheath; allows measurement 3 mm posterior to globe.
Sterile Ultrasound Gel	Parker Laboratories Inc.	AQUASONIC® 100 (Ref 01-08)	Sterile coupling gel applied over closed eyelid to ensure acoustic contact; avoids infection risk.
Sterile Ultrasound Probe Covers	CIVCO Medical Solutions	CIV-FCV-610	Sterile single-use cover for eye scanning; ensures infection control and patient safety.
Patient Monitor (ECG, BP, SpO2)	Philips IntelliVue MX550 / Mindray BeneVision N12	–	Continuous monitoring of vital signs during and after ultrasound measurement.
GCS Assessment Chart / Cognitive Scales	–	–	Standardized Glasgow Coma Scale scoring sheet for serial assessment.
Mini-Mental State Examination (MMSE) Toolkit	Psychological Assessment Resources, Inc.	MMSE-2™	Used to evaluate global cognitive function after patient regains consciousness.
Montreal Cognitive Assessment (MoCA) Form	MoCA Test Inc. (Official license)	–	Used for screening mild cognitive impairment; translated and validated in Chinese population.
Data Collection Sheets / Electronic CRF	Self-designed (SPSS-compatible)	–	Used to record demographic data, ONSD, cognitive scores, and clinical variables.
Statistical Software	IBM Corporation	SPSS v26.0	Used for correlation and regression analyses (ONSD vs. cognitive outcome).
Hospital Information System (HIS)	Wuhan Third Hospital HIS platform	–	Source for retrieving patient demographics and clinical parameters post-ROSC.