Diaphragm UltrasoundPLEASSURE 1NCT07253480
Correlation of Diaphragm Shear-Wave Elastography With Transdiaphragmatic Pressure in Healthy Adults: a Feasibility Study
An observational study of Diaphragm Ultrasound and Diaphragm Dysfunction, run by Isala at 1 site in Netherlands.
Trial summary
Changes in intrapleural pressure after lung volume reduction in Chronic Obstructive Pulmonary disease (COPD) patients can lead to complications, including an increased risk of pneumothorax. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Diaphragm Ultrasound, Diaphragm Dysfunction, Health Adult Subjects
- What is being tested?
- shear wave elastography of the diaphragm
- How many people
- 12 participants
- Where
- 1 siteNetherlands
- Study dates
- Apr 2026to Sep 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: Healthy adults.
Who may be able to join
- 18-60 years, BMI 18-30 kg/m²
- No known respiratory, neuromuscular, or cardiothoracic disease
- Able to perform inspiratory maneuvers and consent.
Who cannot join
- Pregnancy
- History of smoking (> 10 pack years)
- Impaired swallowing, as well as esophageal diseases, or disorders at the level of the gastroesophageal sphincter
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Netherlands1 site
University Medical Centre Groningen
Groningen, Provincie Groningen, 9713GZ
About this study
Changes in intrapleural pressure after lung volume reduction in Chronic Obstructive Pulmonary disease (COPD) patients can lead to complications, including an increased risk of pneumothorax. This procedure, intended to improve lung function, may disturb the pressure balance within the pleural space, potentially precipitating pneumothorax. Careful monitoring of intrapleural pressure could help predict patients at risk. However, intrapleural pressure can currently only be measured invasively. Diaphragm shear-wave elastography (SWE) has been shown to reflect transdiaphragmatic pressure during isovolumetric inspiratory efforts and ventilation against inspiratory loading, and therefore may serve as a non-invasive surrogate for intrapleural pressure. This project outlines a stepwise study plan to evaluate SWE as a tool for intrapleural pressure monitoring (Figure 1). The project only moves to the next phase is the study previous phase was achieved successfully. The current protocol involves the first phase: to validate diaphragm SWE against transdiaphragmatic pressure and assess measurement reliability for local ultrasound systems in healthy adults.This prospective, single-centre, observational validation study will include twelve healthy adult volunteers. During a single study session, participants will perform standardized inspiratory efforts while simultaneous measurements of diaphragm SWE, transdiaphragmatic pressure (via esophageal and gastric balloon catheters), and mouth pressures are obtained. These methods are routinely applied in physiological research and carry minimal risk. Apart from brief nasal or throat discomfort during catheter placement, no significant adverse effects are expected. By establishing the relationship between diaphragm SWE, transdiaphragmatic pressure, and mouth pressures, this study aims to provide the essential validation step for future clinical research in COPD patients following lung volume reduction.
Read the detailed description
Rationale:
Changes in intrapleural pressure after lung volume reduction in COPD patients may contribute to pneumothorax. Non-invasive monitoring of pleural pressure could help identify patients at risk. Diaphragm shear-wave elastography (SWE) has shown potential to reflect transdiaphragmatic pressure (Pdi), but has not yet been validated across ultrasound systems. This study aims to validate diaphragm SWE against gold-standard Pdi and mouth pressures in healthy volunteers before applying the technique in COPD patients.
Objective:
To validate diaphragm SWE as a non-invasive measure of inspiratory effort by assessing its correlation with transdiaphragmatic pressure (Pdi) and mouth pressure (PImax and submaximal inspiratory pressures). Secondary objectives are to determine feasibility and inter-rater reliability of SWE measurements.
Study design:
Prospective, single-centre, observational validation study.
Study population:
Twelve healthy adults aged 18-60 years, BMI 18-30 kg/m², without respiratory, neuromuscular or cardiothoracic disease.
Main study parameters/endpoints:
Participants will undergo simultaneous measurements of diaphragm SWE, transdiaphragmatic pressure (Pdi = Pga-Pes), and inspiratory mouth pressures (Pmo) at rest and during inspiratory efforts at 20%, 40%, and 60% of PImax. SWE will be performed twice by different operators to assess inter-rater reliability. The primary analysis will determine within-individual and overall correlations between SWE and Pdi.
- Pearson correlation coefficient repeated-measures correlation coefficient between SWE and Pdi across inspiratory efforts.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness:
The study involves a single measurement session (~1-2 hours). Procedures include nasal insertion of esophageal and gastric balloon catheters, mouth pressure measurements, and diaphragm ultrasound. These are routinely used physiological techniques with mild, transient, discomfort (e.g., mild throat or nasal irritation). No therapeutic intervention or follow-up is required. Risks are considered negligible and proportionate to the scientific value of the validation.
- Being tested
- shear wave elastography of the diaphragm
- Keywords
- diaphragm, ultrasound, diaphragmatic pressure, shear-wave elastography
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
shear wave elastography of the diaphragmDiagnostic test
Participants will undergo simultaneous measurements of diaphragm SWE, transdiaphragmatic pressure (Pdi = Pga-Pes), and inspiratory mouth pressures (Pmo) at rest and during inspiratory efforts at 20%, 40%, and 60% of PImax. SWE will be performed twice by different operators to assess inter-rater reliability. The primary analysis will determine within-individual and overall correlations between SWE and Pdi.
- Pearson correlation coefficient repeated-measures correlation coefficient between SWE and Pdi across inspiratory efforts.
| Study group | Role | What they receive |
|---|---|---|
| healthy adults | prospective validation cohort of healthy adults Receives: Diagnostic Test: shear wave elastography of the diaphragm |
What is being measured
The primary outcome is the main question the study is designed to answer.
- Pearson correlation coefficient repeated-measures correlation coefficient between SWE and Pdi across inspiratory efforts.
Participants will undergo simultaneous measurements of diaphragm SWE, transdiaphragmatic pressure (Pdi = Pga-Pes), and inspiratory mouth pressures (Pmo) at rest and during inspiratory efforts at 20%, 40%, and 60% of PImax. SWE will be performed twice by different operators to assess inter-rater reliability. The primary analysis will determine within-individual and overall correlations between SWE and Pdi.
Measured: 1 hour
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Nov 2025
- Study startApr 2026 (estimated)
- Primary completionJun 2026 (estimated)
- Study completionSep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Diaphragm UltrasoundStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Isala
- Sponsor type
- University, hospital or other
- Collaborators
- University Medical Center Groningen
- Responsible party
- Principal investigator, Wytze de Boer, University Medical Center Groningen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07253480
- Sponsor's protocol ID
- PLEASSURE 1
- Acronym
- PLEASSURE 1
- Status last verified
- Nov 2025
- First submitted
- 19 Nov 2025
- Last updated
- 5 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: small feasibility study
Study at a glance
From the registry record, last updated by the sponsor on 5 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Correlation of Diaphragm Shear-Wave Elastography With Transdiaphragmatic Pressure in Healthy Adults: a Feasibility Study
- ClinicalTrials.gov ID
- NCT07253480
- Acronym / sponsor ID
- PLEASSURE 1 / PLEASSURE 1
- Keywords
- diaphragm, ultrasound, diaphragmatic pressure, shear-wave elastography
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- IsalaUniversity, hospital or other
- Collaborators
- University Medical Center Groningen
- Study start
- Apr 2026 (estimated)
- Primary completion
- Jun 2026 (estimated)
- Study completion
- Sep 2026 (estimated)
- First posted
- 28 Nov 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Changes in intrapleural pressure after lung volume reduction in Chronic Obstructive Pulmonary disease (COPD) patients can lead to complications, including an increased risk of pneumothorax. This procedure, intended to improve lung function, may disturb the pressure balance within the pleural space, potentially precipitating pneumothorax. Careful monitoring of intrapleural pressure could help predict patients at risk. However, intrapleural pressure can currently only be measured invasively. Diaphragm shear-wave elastography (SWE) has been shown to reflect transdiaphragmatic pressure during isovolumetric inspiratory efforts and ventilation against inspiratory loading, and therefore may serve as a non-invasive surrogate for intrapleural pressure. This project outlines a stepwise study plan to evaluate SWE as a tool for intrapleural pressure monitoring (Figure 1). The project only moves to the next phase is the study previous phase was achieved successfully. The current protocol involves the first phase: to validate diaphragm SWE against transdiaphragmatic pressure and assess measurement reliability for local ultrasound systems in healthy adults.This prospective, single-centre, observational validation study will include twelve healthy adult volunteers. During a single study session, participants will perform standardized inspiratory efforts while simultaneous measurements of diaphragm SWE, transdiaphragmatic pressure (via esophageal and gastric balloon catheters), and mouth pressures are obtained. These methods are routinely applied in physiological research and carry minimal risk. Apart from brief nasal or throat discomfort during catheter placement, no significant adverse effects are expected. By establishing the relationship between diaphragm SWE, transdiaphragmatic pressure, and mouth pressures, this study aims to provide the essential validation step for future clinical research in COPD patients following lung volume reduction.
Detailed description
Rationale:
Changes in intrapleural pressure after lung volume reduction in COPD patients may contribute to pneumothorax. Non-invasive monitoring of pleural pressure could help identify patients at risk. Diaphragm shear-wave elastography (SWE) has shown potential to reflect transdiaphragmatic pressure (Pdi), but has not yet been validated across ultrasound systems. This study aims to validate diaphragm SWE against gold-standard Pdi and mouth pressures in healthy volunteers before applying the technique in COPD patients.
Objective:
To validate diaphragm SWE as a non-invasive measure of inspiratory effort by assessing its correlation with transdiaphragmatic pressure (Pdi) and mouth pressure (PImax and submaximal inspiratory pressures). Secondary objectives are to determine feasibility and inter-rater reliability of SWE measurements.
Study design:
Prospective, single-centre, observational validation study.
Study population:
Twelve healthy adults aged 18-60 years, BMI 18-30 kg/m², without respiratory, neuromuscular or cardiothoracic disease.
Main study parameters/endpoints:
Participants will undergo simultaneous measurements of diaphragm SWE, transdiaphragmatic pressure (Pdi = Pga-Pes), and inspiratory mouth pressures (Pmo) at rest and during inspiratory efforts at 20%, 40%, and 60% of PImax. SWE will be performed twice by different operators to assess inter-rater reliability. The primary analysis will determine within-individual and overall correlations between SWE and Pdi.
- Pearson correlation coefficient repeated-measures correlation coefficient between SWE and Pdi across inspiratory efforts.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness:
The study involves a single measurement session (~1-2 hours). Procedures include nasal insertion of esophageal and gastric balloon catheters, mouth pressure measurements, and diaphragm ultrasound. These are routinely used physiological techniques with mild, transient, discomfort (e.g., mild throat or nasal irritation). No therapeutic intervention or follow-up is required. Risks are considered negligible and proportionate to the scientific value of the validation.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| healthy adults | – | Diagnostic Test: shear wave elastography of the diaphragmprospective validation cohort of healthy adults |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Healthy adults.
Key inclusion criteria (3 listed)
- 18-60 years, BMI 18-30 kg/m²
- No known respiratory, neuromuscular, or cardiothoracic disease
- Able to perform inspiratory maneuvers and consent.
Key exclusion criteria (3 listed)
- Pregnancy
- History of smoking (> 10 pack years)
- Impaired swallowing, as well as esophageal diseases, or disorders at the level of the gastroesophageal sphincter
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| shear wave elastography of the diaphragmParticipants will undergo simultaneous measurements of diaphragm SWE, transdiaphragmatic pressure (Pdi = Pga-Pes), and inspiratory mouth pressures (Pmo) at rest and during inspiratory efforts at 20%, 40%, and 60% of PImax. SWE will be performed twice by different operators to assess inter-rater reliability. The primary analysis will determine within-individual and overall correlations between SWE and Pdi. - Pearson correlation coefficient repeated-measures correlation coefficient between SWE and Pdi across inspiratory efforts. | Diagnostic test | healthy adults |
Primary outcome
- Pearson correlation coefficient repeated-measures correlation coefficient between SWE and Pdi across inspiratory efforts.
Time frame: 1 hour
Participants will undergo simultaneous measurements of diaphragm SWE, transdiaphragmatic pressure (Pdi = Pga-Pes), and inspiratory mouth pressures (Pmo) at rest and during inspiratory efforts at 20%, 40%, and 60% of PImax. SWE will be performed twice by different operators to assess inter-rater reliability. The primary analysis will determine within-individual and overall correlations between SWE and Pdi.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Dec 2025.
- Individual participant dataSharing planned: Undecided. small feasibility study
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Diaphragm Ultrasound and Diaphragm Dysfunction, run by Isala at 1 site in Netherlands.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 5 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Wytze S de Boer, MD ((+31)0646312031 ext. 31, w.s.de.boer@isala.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
- Pearson correlation coefficient repeated-measures correlation coefficient between SWE and Pdi across inspiratory efforts. (time frame: 1 hour). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Dec 2025.