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Air trapping: The major factor limiting diaphragm mobility in chronic obstructive pulmonary disease patients
Author(s) -
DOS SANTOS YAMAGUTI Wellington Pereira,
PAULIN Elaine,
SHIBAO Simone,
CHAMMAS Maria Cristina,
SALGE João Marcos,
RIBEIRO Marcos,
CUKIER Alberto,
CARVALHO Celso Ricardo Fernandes
Publication year - 2008
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/j.1440-1843.2007.01194.x
Subject(s) - medicine , copd , diaphragm (acoustics) , air trapping , pulmonary function testing , cardiology , dynamic hyperinflation , hyperinflation , lung volumes , respiratory system , airway obstruction , lung , airway , anesthesia , monetary policy , physics , acoustics , loudspeaker , monetary economics , economics
Background and objective: Patients with COPD can have impaired diaphragm mechanics. A new method of assessing the mobility of the diaphragm, using ultrasound, has recently been validated. This study evaluated the relationship between pulmonary function and diaphragm mobility, as well as that between respiratory muscle strength and diaphragm mobility, in COPD patients. Methods: COPD patients with pulmonary hyperinflation ( n = 54) and healthy subjects ( n = 20) were studied. Patients were tested for pulmonary function, maximal respiratory pressures and diaphragm mobility using ultrasound to measure the craniocaudal displacement of the left branch of the portal vein. Results: COPD patients had less diaphragm mobility than did healthy individuals (36.5 ± 10.9 mm vs 46.3 ± 9.5 mm, P = 0.001). In COPD patients, diaphragm mobility correlated strongly with pulmonary function parameters that quantify air trapping (RV: r = −0.60, P < 0.001; RV/TLC: r = −0.76, P < 0.001), moderately with airway obstruction (FEV 1 : r = 0.55, P < 0.001; airway resistance: r = −0.32, P = 0.02) and weakly with pulmonary hyperinflation (TLC: r = −0.28, P = 0.04). No relationship was observed between diaphragm mobility and respiratory muscle strength (maximal inspiratory pressure: r = −0.11, P = 0.43; maximal expiratory pressure: r = 0.03, P = 0.80). Conclusion: The results of this study suggest that the reduction in diaphragm mobility in COPD patients is mainly due to air trapping and is not influenced by respiratory muscle strength or pulmonary hyperinflation.