Overview
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.
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.
Eligibility
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.