**Core Concept**
Continuous Positive Airway Pressure (CPAP) is a non-invasive mode of ventilation used to treat obstructive sleep apnea (OSA) by maintaining a constant airway pressure during inspiration and expiration. This prevents the collapse of the upper airway and maintains a patent airway.

**Why the Correct Answer is Right**
CPAP works by increasing the pressure in the airway, which helps to prevent the collapse of the upper airway during sleep. This is achieved through a mask that covers the nose and/or mouth, which is connected to a CPAP machine. The machine delivers a constant flow of air pressure, which is set based on the individual's needs. The increased air pressure helps to keep the airway open, reducing the frequency and severity of apneic events.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, so we cannot evaluate its correctness.
**Option B:** This option is not provided, so we cannot evaluate its correctness.
**Option C:** This option is not provided, so we cannot evaluate its correctness.
**Option D:** This option is not provided, so we cannot evaluate its correctness.

**Clinical Pearl / High-Yield Fact**
A common side effect of CPAP therapy is nasal congestion, which can be managed with saline nasal sprays or humidification devices. It's essential to monitor patients for side effects and adjust the CPAP settings as needed to ensure optimal therapy.

**Correct Answer:** Correct Answer: .