Noninvasive positive pressure ventilation in subjects with stable COPD: a randomized trial

Abstract

Background: The use of domiciliary noninvasive positive pressure ventilation (NPPV) in stable chronic obstructive pulmonary disease (COPD) with chronic hypercapnic respiratory failure has yielded variable effects on survival, quality of life, and dyspnea. We hypothesized that use of NPPV in stable COPD and partial pressure of carbon dioxide (PaCO2) <52 mmHg might result in improvement in quality of life and dyspnea.

Methods: Thirty patients with stable COPD (forced expiratory volume in the first second <50% predicted and PaCO2 <52 mmHg) were prospectively randomized to receive domiciliary NPPV (bilevel positive airway pressure, 15/5 cm H2O) or usual therapy for 6 months. Measurements were made at baseline, 6 weeks, 3 months, and 6 months. Primary outcomes were quality of life as assessed by the Chronic Respiratory Disease Questionnaire (CRQ), and dyspnea as measured by the Transitional Dyspnea Index (TDI).

Results: Fifteen subjects in the NPPV arm and 12 controls completed all the study visits. At 6 weeks and 3 months, the NPPV arm showed significant improvement in TDI total score. However, this effect persisted only in the TDI-Task at 6 months (P=0.03). NPPV use was associated with a small improvement in the CRQ-Mastery domain (0.6 versus -0.1, P=0.04). The arterial partial pressure of oxygen (PaO2) in the control arm worsened over the period of the study, whereas it remained stable in the NPPV arm (change -7.2 mmHg versus +2.1 mmHg, respectively, P=0.02).

Conclusion: NPPV resulted in a small improvement in quality of life indices in stable COPD patients with PaCO2 <52 mmHg. Future larger studies will clarify the role of NPPV in this stable subgroup of patients with COPD.

Keywords: chronic obstructive pulmonary disease; noninvasive; normocapnia; ventilation.

Figure 1

Randomization and follow-up of patients in intervention and control arms. Abbreviations: COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in the first second; FVC, forced vital capacity; PaCO₂, partial pressure of carbon dioxide in arterial blood; NPPV, noninvasive positive pressure ventilation.

Figure 2

Change in dyspnea measured by TDI and quality of life (CRQ-Mastery domain) over time in intervention and control arms. Dots represent control arm; squares represent intervention arm. Notes: *P<0.05 and **P<0.01. Abbreviations: TDI, Transitional Dyspnea Index; CRQ, Chronic Respiratory Disease Questionnaire; NPPV, noninvasive positive pressure ventilation.

Figure 3

Correlation between change in CRQ-Mastery domain and average numbers of hours of use of noninvasive positive pressure ventilation. Abbreviation: CRQ, Chronic Respiratory Disease Questionnaire.