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Glottic closure and high flows are not essential for productive cough
S Young1, N Abdul-Sattar, D Caric
1Department of Physiology, University Medical School, Edinburgh, UK.
Bulletin Europeen De Physiopathologie Respiratoire
|January 1, 1987
Summary
Productive coughing can occur without glottic closure and with low airflow, challenging the long-held belief that high flows and glottic closure are essential for effective sputum expectoration.
Area of Science:
- Respiratory Physiology
- Pulmonology
- Clinical Medicine
Background:
- Historically, glottic closure and high expiratory flows have been emphasized as critical for effective coughing.
- Voluntary coughing mechanics involve complex interactions between thoracic/abdominal pressures and expiratory flow dynamics.
Purpose of the Study:
- To investigate the mechanics of productive coughing, particularly in patients with obstructive airways disease.
- To determine if glottic closure and high airflow are prerequisites for sputum expectoration.
Main Methods:
- Recordings of airflow, volume, and sound during spontaneous coughing in patients with obstructive airways disease.
- Observation of sputum expectoration in relation to cough events.
Main Results:
- Sputum expectoration frequently occurred after groups of coughs following a single inspiration.
- Patients with obstructive airways disease exhibited very low airflow during coughing yet achieved productive results.
- Cough sounds were noted during low-flow periods preceding the expulsive phase, suggesting glottic opening.
Conclusions:
- Productive cough is achievable without glottic closure and with low airflows.
- The findings challenge traditional concepts of cough effectiveness, suggesting alternative mechanisms may be involved in sputum clearance.