Continuous Positive Airway Pressure (CPAP)
The clinical gold standard for Obstructive Sleep Apnoea, utilizing a pneumatic splint to prevent airway collapse. Highly efficacious in lab settings, but severely limited by patient adherence.
Mechanism of Action
CPAP devices deliver a continuous stream of pressurized room air through a mask. This pressure acts as a physical barrier, keeping the soft palate, uvula, and tongue from collapsing into the pharyngeal airway during the muscle relaxation phase of sleep.
Efficacy vs. Effectiveness
When worn correctly and consistently, CPAP eliminates nearly 100% of obstructive apnoea events. However, clinical effectiveness is defined by the formula:
Given that Medicare defines adherence as using the device for ≥4 hours per night on 70% of nights, true clinical effectiveness across the population is drastically lower than the theoretical efficacy.
The Adherence Problem
Long-term studies consistently show that 46% to 83% of patients are non-adherent after 3 years. Primary reasons for abandonment include:
- Mask discomfort and claustrophobia.
- Unintentional mask leaks causing eye irritation or noise.
- Aerophagia (swallowing air, leading to severe bloating).
- Pressure intolerance during exhalation.
Device Types
Clinical Profile
- Primary Indication Mod/Severe OSA
- Efficacy (if used) ~98%
- Avg. Device Cost $800 - $1,500
- Annual Supplies $300 - $600