 There is a growing interest in nocturnal non-invasive mechanical ventilation NIMV therapy for long-term COPD management for several reasons. It may restore inspiratory rate, which diminishes by 30 during rapid eye movement REM sleep, improve gas exchange, and rest chronically tired respiratory muscles in COPD. Indeed, several uncontrolled studies have provided some empirical evidence to support the use of nocturnal NIMV in COPD. However, there is a paucity of well-designed controlled trials evaluating this novel therapy particularly for COPD patients at a high-risk for morbidity and mortality. 