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Expiratory supraglottic obstruction during muscular relaxation
A Sanna1, C Veriter, D Stănescu
1Pulmonary Laboratory and Division, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
Chest
|July 1, 1995
Summary
Upper airway narrowing occurs during muscle relaxation in both healthy individuals and obstructive sleep apnea (OSA) patients. This suggests airway muscles must activate during breathing to maintain an open airway.
Area of Science:
- Respiratory Physiology
- Sleep Medicine
Background:
- Previous studies suggested expiratory upper airway narrowing in obstructive sleep apnea (OSA) patients during sleep and awake states.
- This aligns with the hypothesis of upper airway muscle activation during expiration.
Purpose of the Study:
- To investigate upper airway dynamics during muscular relaxation in healthy volunteers and OSA patients.
- To determine if upper airway narrowing occurs during both inspiration and expiration due to muscle relaxation.
Main Methods:
- Utilized a tank respirator to control breathing in five healthy volunteers and four OSA patients.
- Measured supraglottic pressure, tidal volume, airflow, and diaphragmatic electromyogram.
- Performed fiberoptic bronchoscopy in two healthy subjects to visualize the oropharyngeal isthmus.
Main Results:
- Muscular relaxation led to supraglottic obstruction and flow limitation during both inspiration and expiration.
- Upper airway obstruction was more pronounced in OSA patients compared to healthy subjects.
- Oropharyngeal isthmus narrowing was observed during muscle relaxation in healthy volunteers.
Conclusions:
- Muscle relaxation is associated with upper airway narrowing and flow limitation during both breathing phases.
- Activation of airway muscles during both inspiration and expiration is crucial for maintaining an open upper airway.