Upper Airway Obstruction

This is a prospective, multicenter, observational cohort study enrolling approximately 4,000 subjects across about 50 centers, including patients with COPD (confirmed and suspected), asthma (confirmed and suspected), bronchiectasis, interstitial lung disease (ILD), upper airway obstruction (UAO), and healthy controls. Participants will undergo standardized clinical assessments, cough search, FENO, ETCO2, impulse oscillometry, spirometry, and/or bronchodilator test, and/or bronchoprovocation test, and/or diffusion capacity test at a single baseline visit, with no investigational intervention or treatment assignment. The primary objective is to evaluate the diagnostic performance of portable impulse oscillometry in Chronic respiratory diseases and to develop an artificial intelligence diagnostic model for COPD based on oscillometry. The study duration per subject is limited to the screening/baseline visit, with no follow-up visits planned.

This prospective trial aims to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on airway pressures and oxygenation in adult patients undergoing balloon dilatation under direct laryngoscopy. Airway procedures performed under general anesthesia are associated with unique respiratory mechanics and limited ventilation conditions, making the choice of an optimal ventilation strategy particularly important. Adult patients aged 18-65 years with American Society of Anesthesiologists (ASA) physical status I-III will be allocated to receive either FCV or VCV during surgery. Ventilatory parameters, airway pressures, pulmonary compliance, and arterial blood gas values will be recorded at predefined intraoperative time points. The primary outcome is the PaO₂ measured 20 minutes under an FiO₂ of 0.8-1.0 after starting the ventilation under general anesthesia, reflecting early intraoperative oxygenation under stable conditions. By providing comparative data on respiratory mechanics and oxygenation, this study aims to contribute to the identification of lung-protective ventilation strategies in patients undergoing balloon dilatation under direct laryngoscopy.