Sleep in ventilatory failure in restrictive thoracic disorders. Effects of treatment with non invasive ventilation

Study objectivesHypercapnic ventilatory failure due to restrictive disorders may have a negative impact on sleep architecture. Non-invasive ventilation (NIV) may improve arterial blood gases but may adversely affect sleep. We assessed sleep structure and blood gases before and during NIV in patients with restrictive disorders in hypercapnic ventilatory failure.DesignRetrospective cohort study.SettingSleep laboratory of Saint-Luc University Hospital (Belgium).PatientsChart review of all patients with predominantly restrictive disorders and respiratory failure seen between 1987 and 2008 and evaluated with a baseline polysomnography (PSG) and a PSG under NIV.Measurements and resultsSixty patients aged (mean ± SD) 48 ± 20 years, with total lung capacity of 57 ± 20% of predicted value, PaO2 of 62 ± 16 mm Hg and PaCO2 54 ± 10 mm Hg, were included. At baseline, total sleep time, sleep efficiency, slow wave and rapid-eye movement (REM) sleep were markedly decreased. Conversely, micro-arousals and stage I sleep (N1) were increased. NIV administered with volume-cycled (53%) or pressure-cycled (47%) ventilators improved daytime PaO2, PaCO2, pH and HCO3−. In addition, sleep efficiency, REM sleep, mean and lowest nocturnal SpO2 increased while stage 1, sleep fragmentation, and oxygen desaturation index decreased significantly.ConclusionHypercapnic ventilatory failure in restrictive disorders profoundly affects sleep quality. NIV can improve not only blood gases, but also sleep architecture.