In a sense, oxygen concentrators and Continuous Positive Airway Pressure (CPAP) devices do the same thing: they keep a patient's blood oxygen levels within acceptable limits. But the similarity ends there. The two devices work in completely different ways, and with few exceptions, are used to treat completely different diseases.
What They Do
Oxygen concentrators are supplemental oxygen devices. They provide oxygen-enriched air for the patient to breathe. CPAP machines are basically air pressure devices. In fact, the first models were based on vacuum cleaners. They provide pressurized air to the patient's mask.
What They Treat
Oxygen concentrators are for patients who need extra oxygen to compensate for a variety of heart and lung ailments, such as emphysema and congestive heart failure. CPAP machines are only used to treat one thing: obstructive sleep apnea, a condition in which the airway becomes blocked during sleep, preventing normal breathing.
How They Work
Oxygen concentrators run room air through canisters of filters made of zeolite, which strips nitrogen out of the air, leaving it up to 45 percent richer in oxygen. CPAP machines use a pressure pump to raise air pressure to a specifically prescribed level, and deliver the pressurized air to a mask that seals against the patient's face. The pressure inflates the patient's soft palate, preventing it from prolapsing during sleep and blocking the airway.
Oxygen concentrators and CPAP machines both deliver air to a face mask, but the two masks are designed very differently. Generally CPAP machines deliver much higher pressure to the mask than do oxygen concentrators. The two devices both raise blood oxygen, but the CPAP machine does this by allowing the patient to breathe more efficiently, not by providing supplemental oxygen. The two are sometimes used together for patients who need supplemental oxygen 24 hours a day but also use CPAP at night.