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Cough-enhanced mucus clearance in the normal lung
W D Bennett1, W M Foster, W F Chapman
1Department of Medicine, State University of New York, Stony Brook 11794.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|November 1, 1990
Summary
Coughing significantly enhances mucus clearance from the bronchial airways in healthy individuals. This study shows coughing speeds up the removal of inhaled particles, suggesting mucociliary stimulation.
Area of Science:
- Respiratory Physiology
- Pulmonary Medicine
- Mucociliary Clearance
Background:
- Mucus clearance is vital for lung health.
- The mechanisms by which cough affects mucus clearance are not fully understood.
Purpose of the Study:
- To investigate the effectiveness of voluntary coughing in clearing mucus from the lungs.
- To compare mucus clearance with and without controlled coughing in healthy subjects.
Main Methods:
- 12 healthy, nonsmoking subjects inhaled 99mTc-labeled iron oxide particles.
- Lung activity retention was measured using a gamma camera over 24 hours.
- Subjects underwent a control condition (quiet sitting) and a cough condition (60 controlled coughs in the first hour).
Main Results:
- Coughing significantly reduced particle retention at 1 and 2 hours post-inhalation compared to the control.
- No significant difference in particle retention was observed at 24 hours between cough and control conditions.
- Rapid inhalations also showed enhanced particle clearance, similar to coughing.
Conclusions:
- Voluntary coughing effectively enhances the rate of mucus clearance from the bronchial airways in individuals with normal lung function.
- The enhanced clearance is likely due to stimulation of the mucociliary apparatus, not a two-phase gas-liquid flow mechanism.
- Rapid inhalation techniques may also stimulate mucociliary clearance.