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The expiration reflex from the trachea and bronchi.
M Tatar1, J Hanacek, J Widdicombe
1Dept of Pathophysiology, Faculty of Medicine, Comenius University, Martin, Slovakia.
The European Respiratory Journal
|October 26, 2007
Summary
The expiration reflex (ER) originates in the tracheobronchial tree, not just the larynx. This reflex, distinct from cough, is consistently observed and shares properties with the laryngeal ER.
Area of Science:
- Respiratory Physiology
- Neuroscience
- Pulmonology
Background:
- The expiration reflex (ER) is a protective mechanism involving forced exhalation.
- Its origin is typically attributed to the larynx and vocal folds.
- A potential origin from the tracheobronchial (TB) tree has been hypothesized but not investigated.
Purpose of the Study:
- To determine if the tracheobronchial tree elicits a consistent ER.
- To compare the properties of a tracheobronchial ER (TBER) with the laryngeal ER.
- To re-evaluate the distinction between ER and cough reflexes.
Main Methods:
- Re-analysis of previous studies involving mechanical or chemical stimulation of the TB tree.
- Literature review of studies on TB
- cough
- to support findings.
- Observation of TBER in cats and rabbits.
Main Results:
- A TBER was consistently elicited in cats and rabbits, sometimes preceding or following a cough.
- The TBER was enhanced by lung inflation and general anesthesia, relative to cough.
- The TBER demonstrated properties distinct from a typical cough reflex.
Conclusions:
- The tracheobronchial tree is a source of the expiration reflex.
- The TBER shares characteristics with the laryngeal ER, suggesting a common classification.
- The findings necessitate consideration of TBER in respiratory research and clinical practice.
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