Pathophysiological mechanism of long-term noninvasive ventilation in stable hypercapnic patients with COPD using functional respiratory imaging

Int J Chron Obstruct Pulmon Dis. 2017 Jul 28;12:2197-2205. doi: 10.2147/COPD.S136412. eCollection 2017.


Introduction: Patients with severe COPD often develop chronic hypercapnic respiratory failure. Their prognosis worsens and they are more likely to develop exacerbations. This has major influence on the health-related quality of life. Currently, there is no information about the success of long-term noninvasive ventilation (NIV) among patients who receive NIV in acute settings. Also, little is known about the pathophysiological mechanism of NIV.

Methods: Ten Global Initiative for Obstructive Lung Disease stage III and IV COPD patients with respiratory failure who were hospitalized following acute exacerbation were treated with NIV using a Synchrony BiPAP device for 6 months. Arterial blood gases and lung function parameters were measured. Low-dose computed tomography of the thorax was performed and used for segmentation. Further analyses provided lobe volume, airway volume, and airway resistance, giving an overall functional description of the separate airways and lobes. Ventilation perfusion (VQ) was calculated. Patient-reported outcomes were evaluated.

Results: PaCO2 significantly improved from 50.03 mmHg at baseline to 44.75 mmHg after 1 month and 43.37 mmHg after 6 months (P=0.006). Subjects showed improvement in the 6-minute walk tests (6MWTs) by an average of 51 m (from 332 m at baseline to 359 m at 1 month and 383 m at 6 months). Patients demonstrated improvement in self-reported anxiety (P=0.018). The improvement in image-based VQ was positively associated with the 6MWT and the anxiety domain of the Severe Respiratory Insufficiency Questionnaire.

Conclusion: Though previous studies of long-term NIV have shown conflicting results, this study demonstrates that patients can benefit from long-term NIV treatment, resulting in improved VQ, gas exchange, and exercise tolerance.

Keywords: BiPAP; COPD; exacerbations; functional respiratory imaging; hypercapnia; noninvasive ventilation; ventilation perfusion.

MeSH terms

  • Disease Progression
  • Exercise Tolerance
  • Humans
  • Hypercapnia / diagnostic imaging
  • Hypercapnia / physiopathology
  • Hypercapnia / therapy*
  • Lung / diagnostic imaging*
  • Lung / physiopathology
  • Noninvasive Ventilation / adverse effects
  • Noninvasive Ventilation / instrumentation
  • Noninvasive Ventilation / methods*
  • Patient Reported Outcome Measures
  • Perfusion Imaging / methods*
  • Predictive Value of Tests
  • Pulmonary Disease, Chronic Obstructive / diagnostic imaging*
  • Pulmonary Disease, Chronic Obstructive / physiopathology
  • Pulmonary Disease, Chronic Obstructive / therapy*
  • Pulmonary Gas Exchange
  • Recovery of Function
  • Respiratory Insufficiency / diagnostic imaging
  • Respiratory Insufficiency / physiopathology
  • Respiratory Insufficiency / therapy*
  • Severity of Illness Index
  • Time Factors
  • Tomography, X-Ray Computed*
  • Treatment Outcome