Comparing Two Types of Breathing Support in People With COPD, High Carbon Dioxide Levels, and Sleep Apnea

This pilot study compares two positive airway pressure strategies for patients with both COPD and obstructive sleep apnea (overlap syndrome) who retain excess carbon dioxide. Thirty-two patients will be randomly assigned to either CPAP or high-intensity bilevel ventilation (BiPAP) for 12 months. The primary outcome is change in carbon dioxide levels. Secondary outcomes will be to evaluate the feasibility of conducting a larger multi-centre trial to guide treatment for this underserved population and other measures including sleep quality, respiratory symptoms, quality of life, treatment adherence, side effects, and safety.

Inclusion Criteria * COPD GOLD (Global Initiative for Chronic Obstructive Lung Disease) Group C or D * Daytime PvCO₂ \> 50 mmHg in a stable clinical condition * Obstructive sleep apnea with AHI ≥ 15 events/hour on polysomnography * Body mass index ≥ 30 kg/m² Exclusion Criteria * Conditions associated with central sleep apnea (central apnea index \> 5 events/hour), e.g., left ventricular ejection fraction ≤ 45% or use of high-dose opioids (e.g., morphine) * Current home use of positive airway pressure (PAP) therapy * History of asthma * Cognitive impairment or psychiatric disorders that preclude completion of the study protocol * Pregnancy * Other causes of hypercapnia, e.g., severe kyphoscoliosis or neuromuscular disease