Diaphragm movement and breathing drive in people with OSA, COPD, or both

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

Using ultrasound and surface diaphragm EMG, this cross-sectional study will see if diaphragm movement and breathing drive differ between people with OSA, COPD, both conditions, and healthy adults.

Quick facts

• Study type: Observational
• Enrollment: 80 (estimated)
• Ages: 18 Years to 80 Years
• Sex: All
• Sponsor: Nanjing Medical University (Academic / other)
• Locations: 1 site (Nanjing, Jiangsu)
• Trial ID: NCT07003399 on ClinicalTrials.gov

What this trial studies

This single-center, cross-sectional study compares diaphragmatic structure and respiratory drive across four groups: OSA, COPD, overlap syndrome, and healthy controls. Participants will undergo overnight polysomnography, spirometry, impulse oscillometry, diaphragm ultrasound, and surface diaphragm EMG to measure thickness, excursion, thickening fraction, and EMGdi parameters (rest, max, %max). Investigators will compare group differences and examine relationships between diaphragmatic indicators and respiratory measures such as FEV1, FVC, AHI, and R5-R20. The aim is to identify objective diaphragmatic markers that could characterize dysfunction and help differentiate overlap syndrome.

Who should consider this trial

Good fit: Adults aged 18–80 who can give informed consent and who have OSA (AHI ≥ 5), COPD per GOLD criteria, both conditions (overlap), or are healthy volunteers without respiratory or sleep disorders are ideal candidates.

Not a fit: People with severe cardiovascular, hepatic, or renal disease, neuromuscular disorders affecting respiratory muscles, recent upper airway or thoracic surgery, pregnant or breastfeeding women, or those unable to complete testing are excluded and unlikely to benefit.

Why it matters

Potential benefit: If successful, the findings could provide objective diaphragmatic markers to help distinguish overlap syndrome from OSA or COPD and support more targeted clinical assessment.

How similar studies have performed: Previous work using diaphragm ultrasound and EMG in COPD and some OSA cohorts has shown promising but limited results, while targeted assessment of overlap syndrome remains relatively novel.

Eligibility criteria

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.

Where this trial is running

Nanjing, Jiangsu

• The First Affiliated Hospital of Nanjing Medical University — Nanjing, Jiangsu, China (Recruiting)

Study contacts

• Study coordinator: Ding Ning, doctor

Conditions Obstructive Sleep Apnea; Chronic Obstructive Pulmonary Disease; Overlap Syndrome