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Prolonged expiratory phase in sleep apnea. A unifying hypothesis
The American Review of Respiratory Disease
|March 1, 1985
Summary
This study redefines sleep apnea events, finding expiratory airflow often persists during pauses in breathing. This suggests a need to redefine apneas based on inspiratory airflow absence and highlights increased airway resistance.
Area of Science:
- Respiratory Physiology
- Sleep Medicine
Background:
- The underlying mechanisms of diverse sleep apnea patterns remain unclear.
- Current diagnostic methods may misclassify certain sleep-disordered breathing events.
Purpose of the Study:
- To investigate the airflow dynamics during sleep apnea events.
- To propose a refined definition for sleep apnea events based on airflow characteristics.
Main Methods:
- Analysis of 613 respiratory events in 5 hypersomnolent patients using high-sensitivity airflow recording.
- Categorization of events based on inspiratory effort and airflow presence/absence.
Main Results:
- Expiratory airflow was present during most of the no-inspiratory-effort periods.
- 378 events showed no airflow upon inspiratory effort resumption (occluded).
- 144 events had airflow with inspiratory effort (not-occluded), and 91 suggested airway closure/reopening.
Conclusions:
- Sleep apneas should be defined by the absence of inspiratory airflow, not just inspiratory effort.
- The initial phase of mixed and some central apneas may involve increased expiratory upper airway resistance.