Shear Wave Elastography of Peripheral Nerves for Early Diagnosis of ICU-acquired Weakness

Clinical Value of Shear Wave Elastography of Peripheral Nerves for the Early Diagnosis of ICU-Acquired Weakness: A Prospective Observational Pilot Study

This study aims to determine whether shear wave elastography (SWE), a non-invasive ultrasound technique that measures nerve stiffness, can help detect ICU-acquired weakness (ICU-AW) early in critically ill patients. Adults receiving mechanical ventilation in the ICU will undergo ultrasound examinations of the median and tibial nerves on Days 1, 4, and 7. The study will evaluate whether early changes in nerve elasticity can predict ICU-AW, which is usually diagnosed later using a muscle strength score that requires patient cooperation.

Study Overview

• Status: Not yet recruiting
• Conditions: Critical Illness Myopathy; Critical Illness Polyneuropathy; ICU-acquired Weakness
• Intervention / Treatment: Diagnostic test: Nerve Ultrasound with Shear Wave Elastography

Detailed Description

Intensive Care Unit-Acquired Weakness (ICU-AW) is a common and severe complication in critically ill patients, associated with poor long-term outcomes. The current gold standard for diagnosis, the Medical Research Council (MRC) score, requires patient cooperation and is often delayed.

Shear Wave Elastography (SWE) is an advanced ultrasound technique that quantitatively measures tissue stiffness. Pathophysiological changes in ICU-AW, such as axonal degeneration and edema in nerves, are expected to alter their biomechanical properties (elasticity). This study posits that these changes may be detectable early using SWE, preceding overt clinical weakness.

This study will prospectively enroll adult patients admitted to the ICU who are expected to require prolonged mechanical ventilation. Participants will undergo serial ultrasound examinations of the median and tibial nerves on days 1, 4, and 7 of their ICU stay. The examinations will include SWE to measure nerve elasticity (stiffness) and conventional B-mode ultrasound to measure nerve cross-sectional area (CSA).

On day 7, all consenting and cooperative patients will be assessed for ICU-AW using the MRC score. The primary objective is to determine the diagnostic accuracy of early nerve SWE measurements for predicting the diagnosis of ICU-AW on Day 7. Secondary objectives include describing the dynamic changes in nerve elasticity and size over the first week, and exploring the correlation between these ultrasound parameters and clinical severity scores and patient outcomes.

• Study Type: Observational
• Enrollment (Estimated): 98

Contacts and Locations

• Study Contact: Name: qiancheng xu, PhD; Phone Number: +86-18297529106; Email: xu19871011@163.com

Study Locations

• China
  • Anhui
    • Wuhu, Anhui, China, 241001
      • The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College)
      • Contact: Shengsheng Tao; Phone Number: 86-18315329399; Email: taoshengsheng@yjsyy.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Critically ill adults on mechanical ventilation with an anticipated ICU stay greater than 7 days.

Description

Inclusion Criteria:

1. Age ≥ 18 years;
2. Newly admitted to ICU with an expected ICU stay > 7 days;
3. Initiated on mechanical ventilation within 24 hours of admission, with an expected ventilation duration > 48 hours;
4. Patient or legally authorized representative provides written informed consent.

Exclusion Criteria:

1. Known pre-existing neuromuscular diseases (e.g., myasthenia gravis, Guillain-Barré syndrome, amyotrophic lateral sclerosis);
2. Pre-existing limb dysfunction that would interfere with muscle strength assessment (e.g., hemiplegia, paraplegia, severe arthritis);
3. Presence of acute trauma, surgery, skin breakdown, infection, or severe edema at the measurement sites (wrist, elbow, ankle) that would interfere with ultrasound probe placement;
4. Pregnant or lactating women;
5. Any other condition that the investigator believes would make the patient unsuitable for the study.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

ICU Patients on Mechanical Ventilation; A cohort of adult patients newly admitted to the ICU who are receiving mechanical ventilation and are at risk for developing ICU-Acquired Weakness.

Diagnostic test: Nerve Ultrasound with Shear Wave Elastography; Patients will undergo non-invasive ultrasound examinations of the median nerve and tibial nerve at the bedside on days 1, 4, and 7. The examination includes Shear Wave Elastography (SWE) to quantify nerve stiffness (elasticity) and B-mode imaging to measure nerve cross-sectional area (CSA). This is a purely observational procedure and does not alter patient management.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic Accuracy of Nerve SWE on Day 1 for Predicting ICU-AW on Day 7	Area Under the Receiver Operating Characteristic Curve (AUC) for the mean elasticity value (measured in kilopascals, kPa) of the median and tibial nerves, assessed separately at three time points after ICU admission: Day 1 - to predict ICU-AW diagnosed on Day 7 Day 7 - for concurrent diagnosis of ICU-AW (elastography and MRC assessed independently, blinded to each other) ICU-Acquired Weakness (ICU-AW) is defined as a Medical Research Council (MRC) sum score of less than 48 points.	Day 1 and Day 7 after ICU admission
Diagnostic Accuracy of Nerve SWE on Day 4 for Predicting ICU-AW on Day 7	Area Under the Receiver Operating Characteristic Curve (AUC) for the mean elasticity value (measured in kilopascals, kPa) of the median and tibial nerves, assessed separately at three time points after ICU admission: Day 4 - to predict ICU-AW diagnosed on Day 7 Day 7 - for concurrent diagnosis of ICU-AW (elastography and MRC assessed independently, blinded to each other) ICU-Acquired Weakness (ICU-AW) is defined as a Medical Research Council (MRC) sum score of less than 48 points.	Day 4 and Day 7 after ICU admission
Diagnostic Accuracy of Nerve SWE on Day 7 for Diagnosing ICU-AW on Day 7	Area Under the Receiver Operating Characteristic Curve (AUC) for the mean elasticity value (measured in kilopascals, kPa) of the median and tibial nerves, assessed separately at three time points after ICU admission: Day 7 - for concurrent diagnosis of ICU-AW (elastography and MRC assessed independently, blinded to each other) ICU-Acquired Weakness (ICU-AW) is defined as a Medical Research Council (MRC) sum score of less than 48 points.	Day 7 after ICU admission

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Nerve Elasticity	Absolute and relative change in the shear wave elastography (SWE) value (in kPa) of the median and tibial nerves from baseline (Day 1) to Day 7.	Day 1 to Day 7 after ICU admission
Correlation between Nerve Elasticity and Disease Severity	Spearman's correlation coefficient will be calculated to assess the relationship between the baseline (Day 7) nerve SWE values and the baseline Sequential Organ Failure Assessment (SOFA) score.	Day 7

Collaborators and Investigators

• Sponsor: First Affiliated Hospital of Wannan Medical College

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: May 11, 2026
• First Submitted That Met QC Criteria: May 14, 2026
• First Posted (Actual): May 18, 2026

Study Record Updates

• Last Update Posted (Actual): May 18, 2026
• Last Update Submitted That Met QC Criteria: May 14, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Ultrasonography; Critical Care; Early Diagnosis; Shear Wave Elastography; Peripheral Nerve
• Additional Relevant MeSH Terms: Nervous System Diseases; Pathologic Processes; Neuromuscular Diseases; Peripheral Nervous System Diseases; Pathological Conditions, Signs and Symptoms; Disease; Polyneuropathies
• Other Study ID Numbers: 2026-ICU01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No