How Nocturnal Hypoventilation Predicts Long-term Response to Non-invasive Ventilation in Hypercapnic COPD Patients

The study is an observational, single-center, prospective cohort study aiming to evaluate respiratory mechanics data, as well as clinical and functional parameters commonly used in clinical practice in patients with COPD and hypercapnic respiratory failure. The study population consists of patients with COPD and hypercapnia requiring NIV. The primary objective of the study is to evaluate the association between the reduction in partial pressure of carbon dioxide in arterial blood (PaCO₂) levels at 6 and 12 months after initiating non-invasive ventilation (NIV) and the presence of nocturnal hypoventilation detected at baseline in patients with COPD and chronic hypercapnia. Secondary objectives of this study are the evaluation of the following parameters measured at baseline and/or after 6 and 12 months of NIV treatment in patients with COPD and chronic hypercapnia: * Magnitude of esophageal pressure swing during nocturnal monitoring. * Diaphragm thickness and diaphragmatic thickening fraction assessed by thoracic ultrasound. * Presence of overlap syndrome (COPD + OSA). * Radiological classification of COPD subtypes to assess the association between radiological findings, functional profile, severity of nocturnal hypoventilation, and patterns of chronic hypercapnia. * Respiratory functional parameters, including FEV₁, FVC, FEV₁/FVC ratio, carbon monoxide diffusion capacity (DLCO), and airway resistance (R5 and R20). * Frequency of severe exacerbations and subsequent rehospitalizations during follow-up. * Rate of compliance with respiratory treatment.