Shear Wave Elastography of Intercostal Muscles for the Non-invasive Assessment of the Work of BreathinG (SWING)

Quantifying respiratory effort is a key step in physiological and clinical research on exercise tolerance, mechanisms of fatigability, and ventilatory impairment. To date, reliable assessment relies on an invasive method: esophageal pressure (Pes) measurement using a balloon catheter inserted into the esophagus. Although Pes provides an indirect estimate of pleural and intrathoracic pressure, it is uncomfortable for patients, requires dedicated equipment, and may limit study participation.

In critically ill patients, a noninvasive approach to quantify respiratory effort would have major clinical and scientific value. In acute respiratory distress, accurately tracking the intensity and evolution of respiratory effort could support earlier therapeutic decision-making.

Shear Wave Elastography (SWE) is an ultrasound technology enabling very high acquisition rates and estimating tissue stiffness from shear-wave propagation induced by an acoustic impulse. Because muscle stiffness is strongly related to force produced during contraction, we hypothesize that intercostal muscle stiffness measured by SWE correlates with respiratory work and increases with rising inspiratory load.

Study Overview

• Status: Not yet recruiting
• Conditions: COPD; Healthy Adult
• Intervention / Treatment: Diagnostic test: Intercostal muscle shear wave elastography (SWE) during standardized inspiratory loading

• Study Type: Observational
• Enrollment (Estimated): 20

Contacts and Locations

• Study Contact: Name: Clément Medrinal; Phone Number: +33664615110; Email: medrinal.clement.mk@gmail.com
• Study Contact Backup: Name: Angélique Picard; Email: Angelique.picard@ch-havre.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adults (≥18 years) will be enrolled in two cohorts: (1) healthy adult volunteers and (2) adult patients with chronic obstructive pulmonary disease (COPD), stage 3-4. A total of 20 participants will be recruited (10 COPD patients and 10 healthy volunteers). Each participant will complete a single study visit (~45 minutes) involving standardized breathing/inspiratory loading while intercostal muscle ultrasound shear wave elastography is recorded, with concurrent physiological reference measurements to quantify respiratory effort.

Description

Inclusion Criteria:

Adult patient with chronic obstructive pulmonary disease (COPD), stage 3-4.

Healthy adult volunteer.

Exclusion Criteria:

Refusal to participate or withdrawal of consent.

Age < 18 years.

BMI > 35 kg/m².

Pregnancy or breastfeeding.

Inability to understand instructions or cooperate (cognitive impairment, language barrier).

Neurological condition affecting breathing (e.g., recent stroke, ALS, myopathy).

Thoracic condition limiting access to the intercostal muscles (e.g., major chest wall deformity, surgical scar).

Recent thoracic or abdominal surgery (< 3 months).

Known esophageal disease (stricture, achalasia, severe esophagitis, diverticulum, history of perforation).

ENT or tracheal abnormality preventing probe insertion (e.g., tumor, malformation, tracheostomy).

Swallowing disorders or risk of aspiration.

Recent exacerbation (< 6 weeks).

Oxygen therapy > 2 L/min during exertion.

Hemodynamic instability.

Not affiliated with a social security scheme.

Legally protected persons (as defined by law).

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Healthy adults; Participant without respiratory, muscle or thoracic abnormalities	Diagnostic test: Intercostal muscle shear wave elastography (SWE) during standardized inspiratory loading; Ultrasound shear wave elastography (SWE) is performed to quantify intercostal muscle stiffness at rest and during standardized inspiratory loading/controlled breathing. SWE acquisitions are synchronized with physiological reference recordings (e.g., esophageal pressure and/or diaphragm EMG when available) to estimate and track respiratory effort/work noninvasively.; Other Names: Ultrasound shear wave elastography of intercostal muscles
COPD group; Patients with COPD	Diagnostic test: Intercostal muscle shear wave elastography (SWE) during standardized inspiratory loading; Ultrasound shear wave elastography (SWE) is performed to quantify intercostal muscle stiffness at rest and during standardized inspiratory loading/controlled breathing. SWE acquisitions are synchronized with physiological reference recordings (e.g., esophageal pressure and/or diaphragm EMG when available) to estimate and track respiratory effort/work noninvasively.; Other Names: Ultrasound shear wave elastography of intercostal muscles

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between intercostal muscle stiffness (SWE) and respiratory effort (esophageal pressure-time product)	Intercostal muscle stiffness (kPa) measured by shear wave elastography is correlated with respiratory effort quantified by the esophageal pressure-time product (PTPes; cmH2O·s/min) across the standardized inspiratory loading protocol (within each cohort).	During a single study visit (≈45 minutes), at rest and at each standardized inspiratory load level

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Within-subject change in intercostal muscle stiffness (SWE) across inspiratory load levels	Intercostal muscle stiffness (kPa) measured by shear wave elastography (SWE) will be assessed within participants across the different inspiratory load levels.	Single study visit: during the inspiratory loading protocol (no resistance, then 25%, 50%, and 75% of maximal inspiratory pressure [PiMax])

Collaborators and Investigators

• Sponsor: Groupe Hospitalier du Havre

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2026
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: January 19, 2026
• First Submitted That Met QC Criteria: January 19, 2026
• First Posted (Actual): January 28, 2026

Study Record Updates

• Last Update Posted (Actual): January 28, 2026
• Last Update Submitted That Met QC Criteria: January 19, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: work of breathing; Shear wave elastography; Intercostal muscles
• Additional Relevant MeSH Terms: Pathologic Processes; Chronic Disease; Disease Attributes; Respiratory Tract Diseases; Lung Diseases; Lung Diseases, Obstructive; Pathological Conditions, Signs and Symptoms; Pulmonary Disease, Chronic Obstructive
• Other Study ID Numbers: 2025-A01528-41

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data (IPD) will be made available upon reasonable request. Requests will be reviewed on a case-by-case basis and, if approved, de-identified data and relevant documentation (e.g., protocol and data dictionary) will be shared under an appropriate data use agreement.

Drug and device information, study documents

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