Do you have sleep apnea and are on a CPAP machine or your doctor plans to start you on one? Do you know what your CPAP machine is for?
If you have sleep apnea, it means that your airways are obstructed, which disrupts your breathing throughout the night. If you’re not breathing properly at night, then you’re not getting enough oxygen. The purpose of your CPAP machine is to provide constant air pressure to help keep your airways open to make sure your breathing is normal.
So, if you’re wondering if CPAP will increase blood oxygen, the answer is yes. By maintaining constant air pressure with a CPAP machine, it can maintain normal breathing, and can therefore maintain normal oxygen levels in your blood.
Now, let’s get into the details of how sleep apnea, CPAP therapy, and blood oxygen are all connected.
Does Sleep Apnea Cause Low Oxygen Levels?
When breathing normally while awake, your brain sends signals to the tongue and muscles surrounding the airways to activate them and make them stiffen. This keeps the tongue in place and the airways open and “sturdy” and allows for uninterrupted airflow through the airways and to the lungs.
When we sleep (especially on our backs), there’s a greater risk for the airway behind the tongue to collapse with each breath. This doesn’t usually happen in normal, healthy individuals but does happen in those with obstructive sleep apnea.
In obstructive sleep apnea, the airway therefore gets blocked by the tongue falling into the back of the throat, which obstructs airflow to the lungs. Without enough air getting into the lungs, oxygen levels in the blood decrease and carbon dioxide levels increase.
During obstructive sleep apnea, the brain wakes up at different periods throughout the night and activates your airways so you breathe normally again. It goes back and forth through periods of inactivation (causing obstructed breathing) and activation (causing normal breathing).
The periods of obstructed breathing can last from a few seconds to over a minute. They can also be described as either apnea (pause in breathing) or hypopnea (period of shallow breathing).
Does Oxygen Help Sleep Apnea?
CPAP therapy is currently the main form of treatment for sleep apnea. Studies have shown that CPAP effectively reduces the apnea-hypopnea index (AHI, which is the number of apneas or hypopneas per hour of sleep) and improves low oxygen levels in the blood (also referred to as hypoxemia) caused by respiratory events during sleep.
Studies have also been done to see if administering oxygen is an effective alternative to CPAP for treating sleep apnea.
In an analysis of 14 studies, it was found that patients with obstructive sleep apnea who were treated with CPAP had a significant reduction in AHI compared to those who were administered oxygen overnight.
Interestingly, oxyhemoglobin saturation (or oxygen-saturated hemoglobin molecules in the blood; in other words, blood oxygen saturation) improved the same amount between the CPAP-treated and overnight-oxygen treated patients.
That being said, oxygen administration showed to increase the duration of apnea events, increasing the risk of too much carbon dioxide in the blood.
Overall, it was concluded in these studies that CPAP therapy is preferred over oxygen administration in patients with obstructive sleep apnea. It is generally agreed that oxygen therapy should be reserved for patients who are noncompliant with CPAP and further studies are needed to tell if oxygen can surpass CPAP as a preferred treatment for sleep apnea.
Adding Oxygen to CPAP Therapy
Oxygen therapy may not be considered an acceptable alternative to CPAP therapy at this time, but it can be added to CPAP therapy for certain patients.
Doctors typically recommend adding oxygen to CPAP for older adults, individuals with respiratory diseases such as chronic obstructive pulmonary disorder (COPD), emphysema, or lung cancer, or individuals with a history of low blood oxygen levels overnight.
Oxygen is added to CPAP therapy through a device called an oxygen concentrator. An oxygen supply line from the concentrator can be connected with tubing at either two locations:
- Directly to the CPAP mask via an oxygen port
- Between the CPAP machine and CPAP tubing
If you feel that you aren’t getting the most effective treatment with your CPAP therapy, speak with your doctor about adding oxygen to your treatment regimen. You can also track your oxygen levels at home with a pulse oximeter to see if your oxygen levels are too low and share these readings with your doctor to help you find a treatment plan that works best for you.
Images courtesy of Visual Hunt.
- What Happens During OSA. Harvard.edu. http://healthysleep.med.harvard.edu/sleep-apnea/what-is-osa/what-happens. Accessed October 2020.
- Continuous Positive Airway Pressure (CPAP) Therapy for Obstructive Sleep Apnea. Michigan Medicine. https://www.uofmhealth.org/health-library/hw48752. Accessed October 2020.
- AHI. American Sleep Apnea Association. https://www.sleepapnea.org/ufaqs/what-is-ahi-represent/#:~:text=Apnea%2DHypopnea%20Index%20(AHI),%2C%20on%20average%2C%20each%20hour. Accessed October 2020.
- Understanding the Results. Harvard.edu. http://healthysleep.med.harvard.edu/sleep-apnea/diagnosing-osa/understanding-results. Accessed October 2020.
- Mehta V, Vasu TS, Phillips B, Chung F. Obstructive Sleep Apnea and Oxygen Therapy: A Systematic Review of the Literature and Meta-Analysis. J Clin Sleep Med. 2013;9(3):271-279.
- The Complete Guide to Using CPAP with Oxygen. CPAP.com. https://www.cpap.com/blog/complete-guide-using-cpap-oxygen/. Accessed October 2020.
- Connecting a CPAP Machine to an Oxygen Concentrator. TheCPAPShop.com. https://www.thecpapshop.com/blog/connecting-cpap-to-an-oxygen-concentrator/. Accessed October 2020.