A Continuous Positive Airway Pressure (CPAP) machine does not inherently provide supplemental oxygen. Instead, it delivers a continuous stream of pressurized room air to the user. This device takes air from the surrounding environment and modifies it before delivery. The primary purpose of a CPAP machine is to keep the airway open during sleep, rather than to increase oxygen levels in the blood.
How CPAP Machines Work
CPAP therapy operates by delivering a constant flow of pressurized room air to maintain an open airway during sleep. The machine draws in ambient air, filters it, and then pressurizes it. This pressurized air travels through a hose to a mask, sealed over the nose or mouth. The continuous pressure acts as an “air splint,” preventing upper airway tissues from collapsing.
The main function of this pressurized air is to treat conditions like obstructive sleep apnea (OSA) by physically holding the airway open. Many CPAP machines also include a humidifier, which adds moisture and warmth to the air to prevent dryness and irritation, enhancing comfort. The air used in CPAP therapy is the same natural blend of gases found in the room, primarily nitrogen and about 21% oxygen.
When Supplemental Oxygen is Used
Supplemental oxygen therapy is a distinct medical treatment prescribed for individuals whose bodies do not receive sufficient oxygen from breathing ambient air. This condition, known as hypoxemia, can result from various underlying health issues. Conditions that may necessitate supplemental oxygen include chronic obstructive pulmonary disease (COPD), heart failure, pneumonia, and certain types of sleep apnea like central sleep apnea or severe obstructive sleep apnea with persistent low oxygen levels. Oxygen therapy delivers nearly pure oxygen to increase oxygen saturation in the blood.
Supplemental oxygen can be combined with CPAP therapy when medically indicated. This combination is typically recommended for patients who require both airway pressure to prevent collapse and additional oxygen to improve blood oxygen levels. Oxygen is usually introduced into the CPAP system via a special adapter that connects to the CPAP tubing or directly to a port on the mask, allowing the oxygen to mix with the pressurized air before inhalation. This combined approach ensures the airway remains open while also providing the necessary oxygen enrichment.
CPAP vs. Oxygen Therapy: Key Distinctions
CPAP therapy and oxygen therapy serve different primary functions. CPAP machines primarily provide continuous positive airway pressure to mechanically keep the upper airway open during sleep. This directly treats mechanical breathing problems like airway collapse in obstructive sleep apnea. The effectiveness of CPAP therapy lies in maintaining airway patency, which can indirectly improve blood oxygen levels by preventing breathing interruptions.
In contrast, oxygen therapy delivers additional oxygen to increase its concentration in the bloodstream. This treatment is prescribed for conditions where the body struggles to absorb enough oxygen from the air, regardless of airway patency. While CPAP treats a structural issue in the airway, oxygen therapy addresses a physiological deficiency in oxygen uptake or transport. Both therapies require a medical prescription and can be used independently or, in specific cases, combined under medical guidance to optimize patient outcomes.