Chest
Volume 103, Issue 5, May 1993, Pages 1390-1396
Journal home page for Chest

Clinical Investigations
Regional Impairment of Mucociliary Clearance in Chronic Obstructive Pulmonary Disease

https://doi.org/10.1378/chest.103.5.1390Get rights and content

Asthmatic subjects with tidal expiratory flow limitation have mucociliary clearance (MC) impairment in central airways. Because tidal flow limitation develops in COPD, it is possible that regional MC in these patients also may be affected. We tested this hypothesis by measuring MC in the presence or absence of flow limitations. Patients with COPD and chronic flow limitation were compared with non-flow-limited normal volunteers. Deposition was normalized for regional lung volume and expressed as the specific central to peripheral (sC/P) ratio. In COPD subjects, clearance from the whole lung and central airways was significantly different from that of normal subjects after 20 min of observation. In the peripheral airways, there were no significant differences between COPD and normal subjects. An alternative analysis of regional MC indicated patients retained particles in central airways while normal subjects, with intact MC, emptied central airways. Thus, COPD subjects with tidal expiratory flow limitation have impaired MC in their central airways.

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.

REFERENCES (28)

  • D Yeates et al.

    Characteristics of tracheobronchial deposition and clearance in man

    Ann Occup Hyg

    (1982)
  • T O'Riordan et al.

    Mucociliary clearance in adult asthma

    Am Rev Respir Dis

    (1992)
  • GC Smaldone et al.

    Interpretation of “24 hour lung retention” in studies of mucociliary clearance

    J Aerosol Med

    (1988)
  • GC Smaldone et al.

    Effect of flow-limiting segments and cough on particle deposition and mucociliary clearance in the lung

    Am Rev Respir Dis

    (1979)
  • WM Foster et al.

    Flow limitation on expiration induces central particle deposition and disrupts effective flow of airway mucus

    Ann Occup Hyg

    (1988)
  • GC Smaldone et al.

    Location of flow-limiting segments via airway catheters near residual volume in humans

    J Appl Physiol

    (1985)
  • KW Hyatt et al.

    The flow-volume curve: a current perspective

    Am Rev Respir Dis

    (1973)
  • T Takishima et al.

    Flow-volume curves during quiet breathing, maximum voluntary ventilation and forced vital capacities in patients with obstructive lung disease

    Scand J Respir Dis

    (1967)
  • American Thoracic Society Committee on Diagnostic Standards: Standards for the diagnosis and care of patients with...
  • JS Ilowite et al.

    Relationship between tracheobronchial particle clearance rates and sites of initial deposition in man

    Arch Environ Health

    (1989)
  • WD Bennett et al.

    Cough enhanced mucus clearance in the normal lung

    J Appl Physiol

    (1990)
  • GC Smaldone et al.

    Flow limitation, cough, and patterns of aerosol deposition in humans

    J Appl Physiol

    (1985)
  • GC Smaldone et al.

    Enhancement of particle deposition by flow-limiting segments in humans

    J Appl Physiol

    (1985)
  • WM Foster et al.

    Measurement of tracheal and bronchial mucous velocities in man: relation to lung clearance

    J Appl Physiol

    (1980)
  • Cited by (0)

    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.

    View full text