Chest
Clinical InvestigationsRegional Impairment of Mucociliary Clearance in Chronic Obstructive Pulmonary Disease
Section snippets
Selection of Subjects
We selected nine patients who satisfied the American Thoracic Society definition of COPD8 and who had evidence of expiratory flow volume limitation on tidal respiration.6 In addition, ten volunteers with no history of lung disease and normal flow volume curves were recruited by advertisement. The presence of chronic flow-limitation can be assessed by observing the relationship between the tidal flow-volume loop and the MEFV curve. The individual flow volume curves of all subjects are shown in
RESULTS
Clinical and spirometric data for all subjects are shown in Table 1. The subjects are classified as normal or those with COPD as discussed before. Further, they are subdivided into iron oxide and sebacate deposition groups. There were ten normal subjects (four with iron oxide and six with sebacate deposition). There were nine COPD subjects (four with iron oxide and five with sebacate deposition). The normal group was younger than the COPD group (mean age ± SD = 35 ± 16 years and 56 ± 9 years,
DISCUSSION
This study demonstrates that patients with COPD and chronic flow limitation on tidal breathing have delayed MC that disproportionately affects airways in the central region of the lung. Evidence for the regional impairment is provided by serial sC/P analysis and by classic retention curves. Since MC is thought to be faster in central airways than in peripheral airways in normal subjects, 17, 18 the sC/P ratio would be expected to decrease as inhaled particles are cleared from the central
ACKNOWLEDGMENT
The authors thank Roger Grimson, Ph. D., Department of Preventive Medicine, State University of New York at Stony Brook, for statistical advice.
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Supported by grants HL-00461, AI-16337, HL-31429-07, and ES07088 from the National Institutes of Health.
Manuscript received March 3; revision accepted September 14.