Influence of diaphragmatic mobility on hypercapnia in patients with chronic obstructive pulmonary disease

J Korean Med Sci. 2011 Sep;26(9):1209-13. doi: 10.3346/jkms.2011.26.9.1209. Epub 2011 Sep 1.


A reduction in diaphragm mobility has been identified in patients with chronic obstructive pulmonary disease (COPD) and has been associated with a decline in pulmonary function parameters. However, little information exists regarding the potential role of diaphragm mobility on hypercapnia in COPD. A new method of assessing the mobility of the diaphragm, using ultrasound, has recently been validated. The purpose of the present study was to investigate the relationship between diaphragm mobility and pulmonary function parameters, as well as that between arterial blood gas values and diaphragm mobility, in COPD patients. Thirty seven COPD patients were recruited for pulmonary function test, arterial blood gas analysis and diaphragm mobility using ultrasound to measure the craniocaudal displacement of the left branch of the portal vein. There were significant negative correlations between diaphragmatic mobility and P(a)CO(2) (r = -0.373, P = 0.030). Diaphragmatic mobility correlated with airway obstruction (FEV(1), r = 0.415, P = 0.011) and with ventilatory capacity (FVC, r = 0.302, P = 0.029; MVV, r = 0.481, P = 0.003). Diaphragmatic mobility also correlated significantly with pulmonary hyperinflation. No relationship was observed between diaphragm mobility and P(a)O(2) (r = -0.028, P = 0.873). These findings support a possibility that the reduction in diaphragm mobility relates to hypercapnia in COPD patients.

Keywords: Diaphragm mobility; Hypercapnia; Pulmonary Disease, Chronic Obstructive; Ultrasonography.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Airway Resistance / physiology
  • Carbon Dioxide / blood
  • Carbon Dioxide / physiology
  • Diaphragm / diagnostic imaging*
  • Diaphragm / physiopathology
  • Female
  • Humans
  • Hypercapnia / complications
  • Hypercapnia / physiopathology*
  • Male
  • Middle Aged
  • Portal Vein
  • Pulmonary Disease, Chronic Obstructive / complications
  • Pulmonary Disease, Chronic Obstructive / diagnostic imaging
  • Pulmonary Disease, Chronic Obstructive / physiopathology*
  • Pulmonary Gas Exchange
  • Respiratory Muscles / physiopathology
  • Ultrasonography


  • Carbon Dioxide