Oxygen therapy is sometimes used to treat obstructive sleep apnea (OSA), due to a condition called hypoxemia that can result from overnight interruptions in breathing. It’s important to learn what role oxygen can play in treating OSA and whether other options, such as continuous positive airway pressure (CPAP) therapy, may be a better choice for you.
Oxygen in Sleep Apnea
If a healthcare provider suspects you have sleep apnea, they’ll likely send you for a sleep study in a sleep laboratory to confirm the diagnosis, although it is sometimes possible to complete the study in your own home. Because OSA can cause your oxygen levels to drop while you sleep (a condition called hypoxemia or hypoxia), your healthcare provider may prescribe supplemental oxygen for you to use while you sleep. Oxygen therapy is often used for patients who are not somnolent (drowsy) or not compliant with CPAP.
Often, overnight oximetry will be used to monitor the oxygen levels and pulse rate is measured overnight with a sensor placed on a fingertip. You have hypoxemia if your oxygen levels dip below 88% for more than five minutes.
The oxygen is delivered through plastic tubing called a nasal cannula, typically at a rate of several liters per minute.
While the reasoning behind oxygen therapy may seem sound, it doesn’t improve the other symptoms of OSA, such as carbon dioxide retention and fragmented sleep.
That’s because obstructive sleep apnea is often due to the collapse of the tissues of the upper airway. If the throat is partially or completely closed, it doesn’t matter how much oxygen is delivered via a nasal cannula, it still may not reach the lungs. If the oxygen can’t get where it needs to go, it can’t be effective.
Why Oxygen Isn’t Enough
Using supplemental oxygen in people with OSA but otherwise normal respiratory function has mixed results. While the measured oxygen level will improve, the treatment’s effect on the apnea-hypopnea index (AHI) and the length of apneic events (interruptions in breathing) is negligible.
Additionally, excessive daytime sleepiness, which is a significant complaint in people with the condition, does not improve with oxygen because the oxygen doesn’t prevent the sleep interruptions.
At the same time, the use of oxygen may give people a false sense of protection while the condition and its associated symptoms remain inadequately treated. Individuals with OSA have a greater chance of suffering a stroke or a heart attack, or of dying from a cardiovascular problem. For this reason, proper treatment adherence is of paramount importance.
Moreover, oxygen use alone does not improve the levels of excessive carbon dioxide that may accumulate during sleep, and this can be dangerous.
A Case for CPAP + Oxygen?
Because OSA is associated with high blood pressure, researchers have looked into the role of supplemental oxygen in addition to CPAP.
A study published in 2019 sought to establish the role of intermittent hypoxia (a state of low oxygen in the tissues) in the morning high blood pressure (hypertension) that’s common in people with OSA. They found that supplemental oxygen virtually eliminated they typical rise in morning blood pressure but didn’t address other symptoms of OSA, such as morning heart rate or daytime sleepiness. They concluded that hypertension linked to OSA is the result of hypoxia and not sleep interruption.
On the surface, that conclusion appears to be at odds with the findings of a 2014 study that investigated the impact of supplemental oxygen and CPAP together on markers of cardiovascular risk. This paper concluded that, in people with heart disease or multiple risk factors of heart disease, CPAP did reduce blood pressure while supplemental oxygen at night did not.
However, an important difference between the studies is that the 2014 one looked at overall blood pressure, while the later one focused only on morning blood pressure.
There is much the experts still don’t know about the link between OSA and hypertension and how best to deal with it, so more research needs to be done.
Oxygen for Sleep Apnea With COPD
In some situations, using oxygen to treat sleep apnea may actually be dangerous. In people with only a chronic obstructive pulmonary disease (COPD), such as emphysema, oxygen has been shown to be beneficial. However, when COPD occurs alongside obstructive sleep apnea, a different picture emerges.
In this so-called “overlap syndrome,” the use of nighttime oxygen without CPAP or bilevel therapy can actually cause your overnight breathing to get worse. Your carbon dioxide levels may increase, which can cause morning headaches or confusion. Therefore, it is important that you treat your sleep apnea so that it’s safe to use oxygen for COPD.
Overlap syndrome makes it especially important for people with COPD to have a sleep study if sleep apnea is suspected.
Oxygen therapy may be added to CPAP or bilevel therapy if the oxygen levels remain low overnight for people whose lungs aren’t able to extract enough oxygen even when the airway is kept open.
A Word From Get Meds Info
If you’re concerned about your breathing during sleep, speak with a board-certified sleep specialist and get the treatment that you need. A formal sleep study may be the first step toward optimizing your health and well-being.