Airflow pattern complexity during resting breathing in patients with COPD: effect of airway obstruction

Respir Physiol Neurobiol. 2014 Feb 1;192:39-47. doi: 10.1016/j.resp.2013.12.004. Epub 2013 Dec 12.


We investigated the influence of airway obstruction in the complexity of the airflow pattern in COPD and its use as a marker of disease activity. The sample entropy (SampEnV') and the variability (SDV') of the airflow pattern were measured in a group of 88 subjects with various levels of airway obstruction. Airway obstruction resulted in a reduction in the SampEnV' (p<0.0001) that was significantly correlated with spirometric indices of airway obstruction (R=0.50, p<0.001). The early adverse effects in mild airway obstruction were detected by the SampEnV' with an accuracy of 84%. SDV' increased with airway obstruction (p<0.002). We conclude that (1) the airflow patterns in COPD exhibit reduced complexity compared with healthy subjects; (2) this reduction in complexity is proportional to airway obstruction; and (3) the evaluation of SampEnV' may provide novel respiratory biomarkers suitable to facilitate the diagnosis of respiratory abnormalities in COPD.

Keywords: COPD; Complexity; Diagnostic; Homeokinesis; Sample entropy; Variability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Air Movements
  • Airway Resistance / physiology
  • Entropy
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pulmonary Disease, Chronic Obstructive / physiopathology*
  • Pulmonary Ventilation / physiology*
  • Respiratory Function Tests / methods
  • Rest / physiology*
  • Spirometry
  • Statistics, Nonparametric
  • Tidal Volume / physiology
  • Vital Capacity / physiology