title: 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Pulmonary, Critical Care, and Occupational Medicine, Department of Internal Medicine, Roy J and Lucille A, Carver College of Medicine, University of Iowa Hospital, Iowa City, IA, USA.
authors.forename: Surya P
authors.initials: SP
authors.lastname: Bhatt
authors.forename: Michael W
authors.initials: MW
authors.lastname: Peterson
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Wilson
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Durairaj
mesh_terms: D000368:Aged; D004417:Dyspnea / Q000503:physiopathology / Q000628:therapy; D005260:Female; D006699:Home Care Services; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D063087:Noninvasive Ventilation; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D011788:Quality of Life; D020127:Recovery of Function; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome
keywords: chronic obstructive pulmonary disease; noninvasive; normocapnia; ventilation