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Dynamic modulation of upper airway function during sleep: a novel single-breath method
Jason P Kirkness1, Alan R Schwartz, Susheel P Patil
1John Hopkins Sleep Disorders Center, Baltimore, MD 21224, USA. jason_kirkness@jhmi.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|July 11, 2006
Summary
Upper airway collapsibility dynamically changes during sleep apnea. Closing pressure is lower than opening pressure, indicating variable airway function throughout the respiratory cycle.
Area of Science:
- Respiratory Physiology
- Sleep Medicine
- Biomedical Engineering
Background:
- Sleep apnea involves dynamic upper airway (UA) function.
- Understanding UA collapsibility is crucial for effective treatment.
Purpose of the Study:
- To investigate dynamic UA modulation during sleep.
- To measure critical pressure (Pcrit) and airflow resistance (Rus) during breathing cycles.
Main Methods:
- Developed a novel method to measure Pcrit in tracheostomized sleep apnea patients.
- Recorded tracheal pressure and airflow during transtracheal insufflation.
- Analyzed pressure-flow relationships during inspiration and expiration.
Main Results:
- UA collapsibility (Pcrit) and resistance (Rus) varied dynamically throughout the respiratory cycle.
- UA closing pressure (4.4 cm H2O) was significantly lower than opening pressure (10.8 cm H2O).
- Upstream resistance (Rus) was higher during deflation than inflation.
Conclusions:
- UA collapsibility is not static but changes dynamically during sleep.
- Mechanical and neuromuscular factors likely contribute to UA function modulation.
- Findings offer new insights into the pathophysiology of sleep apnea.