How does continuous positive airway pressure (CPAP) work in obstructive sleep apnea (OSA)?

Updated: Sep 15, 2020
  • Author: Himanshu Wickramasinghe, MD, MBBS; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Answer

Effectively, CPAP acts as a pneumatic splint to maintain UA patency during sleep, preventing the soft tissues from collapsing. By this mechanism, it effectively eliminates the apneas and/or hypopneas, decreases the arousals, and normalizes the oxygen saturation (see the image below).

Effect of nasal continuous positive airway pressur Effect of nasal continuous positive airway pressure (CPAP) on oxygen saturation in sleep apnea. The upper portion of this figure shows the raw oxygen saturation trace from 1 night of a sleep study. Below the raw trace are vertical lines that indicate the presence of either an apnea or hypopnea. Before CPAP, frequent respiratory events with significant desaturations occurred. During the night, CPAP was applied, resulting in the elimination of the apnea and hypopneas and normalization of the oxygen trace.

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