Plain-language definitions grounded in the clinical and regulatory literature.
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Treatment
What it isA therapy that uses a bedside machine to deliver steady air pressure through a mask, keeping your airway open during sleep.
Why it mattersCPAP is the gold-standard treatment for obstructive sleep apnea, but about half of patients struggle to tolerate it long-term.
Think of it like thisThink of a bouncy castle that stays inflated because air is constantly pumped in. CPAP works the same way for your airway—constant pressure keeps the ‘walls’ from collapsing.
Continuous positive airway pressure (CPAP) is a form of non-invasive positive pressure ventilation that maintains a constant level of positive pressure in the upper airway throughout the respiratory cycle, acting as a pneumatic splint to prevent pharyngeal collapse during sleep.
MechanismCPAP creates a pressure gradient that exceeds the critical closing pressure (Pcrit) of the upper airway, preventing the negative intraluminal pressure generated during inspiration from causing pharyngeal collapse. The delivered pressure is typically titrated during polysomnography to determine the minimum effective pressure.
Scientific ConsensusCPAP effectively reduces AHI to near-normal levels when used consistently and is associated with reduced cardiovascular risk, improved cognitive function, and decreased daytime sleepiness. The therapy is considered first-line treatment for moderate-to-severe OSA.
Active DebateWhether comfort-focused modifications to pressure delivery patterns can improve real-world adherence without compromising efficacy, and what the optimal balance is between therapeutic pressure and patient tolerance.
Emerging ResearchWhether constant inspiratory pressure is necessary for airway patency, or whether pressure delivery can be optimized to specific phases of the breathing cycle; The role of loop gain and arousal threshold in determining CPAP efficacy and tolerance
Key ResearchSullivan et al. (1981) first demonstrated CPAP efficacy in treating OSA. Subsequent work by Schwartz, Smith, and colleagues established the concept of critical closing pressure. The SAVE trial (McEvoy et al., 2016) examined cardiovascular outcomes with CPAP.
— American Academy of Sleep Medicine systematic review and GRADE assessment of positive airway pressure for adult OSA
— SAVE trial: CPAP for prevention of cardiovascular events in OSA, establishing evidence for CV outcomes
— Meta-analysis of CPAP efficacy for cardiovascular event prevention in OSA patients
— ATS official statement on CPAP adherence tracking systems and optimal monitoring strategies
Weaver TE & Grunstein RR (2008)
— Comprehensive review of CPAP adherence factors and strategies to improve compliance
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