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NCT Number: NCT07003399

Diaphragmatic Function and Respiratory Drive in OSA and COPD

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.

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Key information

Conditions

Obstructive Sleep Apnea Apnea Chronic Disease Disease Attributes Dyssomnias Lung Diseases Lung Diseases, Obstructive Nervous System Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Pulmonary Disease, Chronic Obstructive Respiration Disorders Respiratory Tract Diseases Sleep Apnea Syndromes Sleep Apnea, Obstructive Sleep Disorders, Intrinsic Sleep Wake Disorders

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Observational

Primary location

The First Affiliated Hospital of Nanjing Medical University

Nanjing, Jiangsu, 210029, China

Location status: Recruiting

Location contact

Ding Ning, doctor

CONTACT

[email protected]

86-25-68136723

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

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

Treatment and study plan

Diaphragmatic Ultrasound and EMG Assessment

Other

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.

Primary outcomes

  1. 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.

  2. 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.

  3. 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.

Secondary outcomes

  1. 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.

  2. Respiratory impedance parameter R5

    Time frame: Baseline (at enrollment)

    To compare small airway resistance (kPa·s·L-¹) between groups using impulse oscillometry.

  3. Respiratory resistance at 20 Hz (R20)

    Time frame: Baseline (at enrollment)

    To compare central airway resistance (kPa·s·L-¹) using impulse oscillometry.

  4. 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) .

  5. 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.

  6. Forced vital capacity (FVC)

    Time frame: Baseline (at enrollment)

    To compare FVC (L) across groups and assess pulmonary capacity.

  7. FEV1/FVC ratio

    Time frame: Baseline (at enrollment)

    To evaluate airflow obstruction using the FEV1/FVC ratio (%).

  8. Apnea-hypopnea index (AHI)

    Time frame: Baseline (at enrollment)

    To evaluate sleep-disordered breathing severity (events/hour) in OSA and Overlap groups.

  9. Oxygen desaturation index (ODI)

    Time frame: Baseline (at enrollment)

    To assess oxygen desaturation frequency during sleep (events/hour) using PSG data.

  10. Minimum oxygen saturation (SpO₂ min)

    Time frame: Baseline (at enrollment)

    To capture the lowest oxygen saturation (%) during overnight monitoring.

  11. Time below 90% oxygen saturation (T90)

    Time frame: Baseline (at enrollment)

    To calculate the percentage of sleep time with oxygen saturation < 90% (%).

Study contacts

Contact information is provided by the study sponsor or research team.

Ding Ning, doctor

CONTACT

[email protected]

86-25-68136723

Sponsors and collaborators

Lead sponsor

Nanjing Medical University

Other

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Jun 4, 2025
Registry last updated
Jun 25, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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