Diaphragmatic Function and Respiratory Drive in OSA and COPD

June 24, 2025 updated by: Ning Ding, Nanjing Medical University

Diaphragmatic Morphofunction and Respiratory Drive in OSA and COPD: Insights From Ultrasound and EMG-based Cross-Sectional Analysis

This cross-sectional observational study aims to assess the diaphragmatic morphofunction and respiratory drive characteristics among patients with obstructive sleep apnea (OSA), chronic obstructive pulmonary disease (COPD), overlap syndrome (OS), and healthy controls. Using ultrasound imaging and surface diaphragm electromyography (EMGdi), the study will explore group differences in diaphragmatic morphology, function, and respiratory drive indicators, and evaluate their clinical significance in disease differentiation and severity assessment.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a single-center cross-sectional study designed to compare the diaphragmatic morphofunction and respiratory drive among four groups: OSA, COPD, overlap syndrome (patients with both OSA and COPD), and healthy controls. Participants will undergo overnight polysomnography (PSG), spirometry, impulse oscillometry, and diaphragm ultrasound combined with surface EMGdi measurements. The study will analyze group differences in diaphragmatic thickness, excursion, thickening fraction, and EMGdi parameters including EMGdi-rest, EMGdi-max, and EMGdi%max. The relationships between diaphragmatic indicators and respiratory parameters (FEV1, FVC, AHI, R5-R20, etc.) will also be assessed. This study aims to provide objective evidence for diaphragmatic dysfunction characterization in OSA and COPD, as well as to explore its diagnostic utility in overlap syndrome.

Study Type

Observational

Enrollment (Estimated)

80

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • China
    • Jiangsu
      • Nanjing, Jiangsu, China, 210029
        • Recruiting
        • The First Affiliated Hospital of Nanjing Medical University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Patients diagnosed with obstructive sleep apnea, chronic obstructive pulmonary disease, overlap syndrome (OSA and COPD), and healthy volunteers from a single center. Subjects will be evaluated for diaphragmatic morphofunction and respiratory drive using ultrasound and EMG.

Description

Inclusion Criteria:

  1. Patients aged between 18 and 80 years.
  2. For OSA Group: Diagnosed obstructive sleep apnea with AHI ≥ 5 events/hour based on overnight polysomnography.
  3. For COPD Group: Diagnosed chronic obstructive pulmonary disease based on GOLD guidelines.
  4. For Overlap Group: Diagnosed both OSA (AHI ≥ 5) and COPD.
  5. For Control Group: Healthy volunteers with no known respiratory diseases or sleep disorders.
  6. Ability and willingness to provide informed consent for participation in the study.

Exclusion Criteria:

  1. Severe cardiovascular diseases (e.g., unstable angina, heart failure NYHA III/IV).
  2. Severe hepatic or renal insufficiency.
  3. Neuromuscular diseases affecting respiratory muscles.
  4. Recent upper airway or thoracic surgery (within 3 months).
  5. Pregnancy or breastfeeding.
  6. Participants who cannot complete assessments due to cognitive impairment or poor cooperation.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Normal Group
Healthy subjects with no known respiratory diseases or sleep disorders, serving as the control group for baseline comparison of diaphragmatic function and respiratory drive.
Other: Diaphragmatic Ultrasound and EMG Assessment
Non-invasive assessment of diaphragmatic morphofunction and respiratory drive using ultrasound imaging and diaphragm electromyography (EMG). This evaluation will be performed once per participant without any therapeutic intervention.
OSA Group
Patients diagnosed with obstructive sleep apnea (OSA) based on polysomnography criteria (AHI ≥ 5 events/hour), evaluated for diaphragmatic function and respiratory drive using ultrasound and EMG.
Other: Diaphragmatic Ultrasound and EMG Assessment
Non-invasive assessment of diaphragmatic morphofunction and respiratory drive using ultrasound imaging and diaphragm electromyography (EMG). This evaluation will be performed once per participant without any therapeutic intervention.
COPD Group
Patients diagnosed with chronic obstructive pulmonary disease (COPD) based on GOLD guidelines, assessed for diaphragmatic morphofunction and respiratory drive.
Other: Diaphragmatic Ultrasound and EMG Assessment
Non-invasive assessment of diaphragmatic morphofunction and respiratory drive using ultrasound imaging and diaphragm electromyography (EMG). This evaluation will be performed once per participant without any therapeutic intervention.
Overlap Group
Patients with overlap syndrome (coexisting OSA and COPD), evaluated for diaphragmatic function and respiratory drive using ultrasound and EMG to explore combined disease impact.
Other: Diaphragmatic Ultrasound and EMG Assessment
Non-invasive assessment of diaphragmatic morphofunction and respiratory drive using ultrasound imaging and diaphragm electromyography (EMG). This evaluation will be performed once per participant without any therapeutic intervention.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Diaphragmatic electromyography (EMGdi-rest) at baseline
Time Frame: Baseline (at enrollment)
To assess resting diaphragmatic electromyographic activity (µV) across OSA, COPD, Overlap, and control groups using surface and esophageal EMG.
Baseline (at enrollment)
Diaphragmatic EMG during maximal inspiration (EMGdi-max)
Time Frame: Baseline (at enrollment)
To assess maximal inspiratory diaphragmatic EMG activity (µV) using voluntary effort tests with surface and esophageal EMG.
Baseline (at enrollment)
Relative inspiratory EMG effort (EMGdi%max)
Time Frame: Baseline (at enrollment)
To calculate the ratio of EMGdi-rest to EMGdi-max as a percentage, reflecting the relative inspiratory effort.
Baseline (at enrollment)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Diaphragmatic excursion measured by ultrasound during deep breathing
Time Frame: Baseline (at enrollment)
To evaluate diaphragmatic mobility (cm) during deep breathing using standardized ultrasound protocols.
Baseline (at enrollment)
Respiratory impedance parameter R5
Time Frame: Baseline (at enrollment)
To compare small airway resistance (kPa·s·L-¹) between groups using impulse oscillometry.
Baseline (at enrollment)
Respiratory resistance at 20 Hz (R20)
Time Frame: Baseline (at enrollment)
To compare central airway resistance (kPa·s·L-¹) using impulse oscillometry.
Baseline (at enrollment)
Difference in resistance (R5-R20)
Time Frame: Baseline (at enrollment)
To evaluate small airway dysfunction by calculating the difference between R5 and R20 (kPa·s·L-¹) .
Baseline (at enrollment)
Forced expiratory volume in 1 second (FEV1)
Time Frame: Baseline (at enrollment)
To compare FEV1 (L) across groups and assess its relationship with diaphragmatic function.
Baseline (at enrollment)
Forced vital capacity (FVC)
Time Frame: Baseline (at enrollment)
To compare FVC (L) across groups and assess pulmonary capacity.
Baseline (at enrollment)
FEV1/FVC ratio
Time Frame: Baseline (at enrollment)
To evaluate airflow obstruction using the FEV1/FVC ratio (%).
Baseline (at enrollment)
Apnea-hypopnea index (AHI)
Time Frame: Baseline (at enrollment)
To evaluate sleep-disordered breathing severity (events/hour) in OSA and Overlap groups.
Baseline (at enrollment)
Oxygen desaturation index (ODI)
Time Frame: Baseline (at enrollment)
To assess oxygen desaturation frequency during sleep (events/hour) using PSG data.
Baseline (at enrollment)
Minimum oxygen saturation (SpO₂ min)
Time Frame: Baseline (at enrollment)
To capture the lowest oxygen saturation (%) during overnight monitoring.
Baseline (at enrollment)
Time below 90% oxygen saturation (T90)
Time Frame: Baseline (at enrollment)
To calculate the percentage of sleep time with oxygen saturation < 90% (%).
Baseline (at enrollment)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Nanjing Medical University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2025

Primary Completion (Estimated)

August 31, 2025

Study Completion (Estimated)

August 31, 2025

Study Registration Dates

First Submitted

May 15, 2025

First Submitted That Met QC Criteria

May 25, 2025

First Posted (Actual)

June 4, 2025

Study Record Updates

Last Update Posted (Estimated)

June 25, 2025

Last Update Submitted That Met QC Criteria

June 24, 2025

Last Verified

June 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2021-SR-347

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The individual participant data will not be shared. The informed consent will be ansigned before enrolled in the study and ensured to keep personal information confidential.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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