A Continuous Positive Airway Pressure (CPAP) machine does not provide supplemental oxygen. It treats sleep apnea by delivering a steady stream of pressurized room air, maintaining an open airway during sleep and preventing breathing interruptions.
How CPAP Works
A CPAP machine operates by generating a continuous flow of air pressure, delivered through a hose and mask worn over the nose or mouth. This constant pressure acts like an “air splint,” gently pushing against the soft tissues in the throat. The sustained pressure prevents the upper airway from collapsing, which is the underlying cause of obstructive sleep apnea.
The machine draws in ambient air, filters it, and then pressurizes it to a prescribed level. This pressurized air keeps the pharynx open, ensuring an unobstructed path for breathing. Maintaining an open airway prevents episodes of apnea (complete cessation of breathing) and hypopnea (partial reduction in breathing) that disrupt sleep. By eliminating these breathing interruptions, CPAP therapy allows for continuous, restorative sleep and improves oxygen saturation levels.
CPAP and Oxygen: Key Differences
CPAP therapy and supplemental oxygen therapy serve distinct medical purposes. CPAP focuses on the mechanical aspect of breathing, providing continuous air pressure to keep the airway physically open. The air delivered by a CPAP machine is room air, composed of about 21% oxygen, 78% nitrogen, and trace gases.
Conversely, supplemental oxygen therapy increases the concentration of oxygen in the air a person breathes. This is achieved by delivering pure oxygen or oxygen-enriched air from a separate source, such as an oxygen tank or concentrator. The goal of oxygen therapy is to raise low blood oxygen levels (hypoxemia) by providing a higher percentage of oxygen than found in ambient air. While CPAP addresses airway structural issues, oxygen therapy directly targets the gas exchange process in the lungs.
When Oxygen Therapy is Prescribed
Oxygen therapy is prescribed when lungs cannot adequately transfer oxygen into the bloodstream, leading to low blood oxygen levels, known as hypoxemia. Various medical conditions can cause hypoxemia, including chronic obstructive pulmonary disease (COPD), severe asthma, pneumonia, cystic fibrosis, and heart failure. Oxygen therapy ensures enough oxygen reaches the body’s tissues and organs to function properly.
Supplemental oxygen can be delivered through devices such as nasal cannulas, face masks, or a tracheostomy. In some cases, individuals may require both CPAP and supplemental oxygen therapy simultaneously. This combined approach is for patients with obstructive sleep apnea and a separate medical condition causing chronic low blood oxygen levels. CPAP addresses airway obstruction, while oxygen addresses the gas exchange deficiency.