Background: Sleep hypoventilation has been proposed as a cause of progressive hypercapnic respiratory failure and death in patients with severe chronic obstructive pulmonary disease (COPD).
Objective: To determine the effects of nocturnal, non-invasive bi-level pressure support ventilation (NIV) on survival, lung function and quality of life in severe hypercapnic COPD.
Design: A multicentre, open-label, randomized controlled trial of NIV plus long term oxygen therapy (LTOT) versus LTOT alone.
Setting: University Hospital sleep/ respiratory medicine departments.
Patients: Severe, stable, smoking-related COPD (FEV1.0 < 1.5 L or <50% predicted and FEV1.0/FVC <60% with awake PaCO2 > 46mmHg and on LTOT for at least 3 months) and age less than 80 years. Patients with sleep apnea (Apnea-hypopnea Index > 20/ hr) or morbid obesity (BMI >40) were excluded.
Intervention: Night-time bilevel pressure support ventilation.
Measurements: Survival, spirometry, arterial blood gases, polysomnography, general and disease specific quality of life, and mood.
Results: 144 patients were randomized: 72 to NIV + LTOT and 72 to LTOT alone. NIV improved sleep quality and sleep-related hypercapnia acutely, and patients complied well with therapy (mean nightly use 4.5 hours, SD 3.2 hours). Compared with LTOT alone, NIV (mean follow-up 2.21 years, range 0 – 5.59 years) resulted in a small improvement in survival (adjusted hazard ratio, 95% CI: 0.63, 0.40 – 0.99; p = 0.045). FEV1.0 and PaCO2 measured at 6 and 12 months were not different between groups. Patients assigned to NIV + LTOT had reduced general and mental health and vigor.
Conclusions: Nocturnal NIV in stable, oxygen dependent, hypercapnic COPD patients may improve survival but this appears to be at the cost of worsening quality of life.