Does Mouth Breathing Affect My Oxygen Levels?

The Effect of Mouth vs Nose Breathing on Oxygen Levels

Woman's Mouth
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Does mouth breathing affect your oxygen levels if you are on supplemental oxygen therapy? If so, what do you need to know and what can you do about it?

Supplemental Oxygen Therapy Basics

Supplemental oxygen therapy is generally prescribed to people whose partial pressure of oxygen (PaO2) as measured by arterial blood gases (ABGs) is less than or equal to 55 mg Hg and a documented oxygen saturation level of 88 percent or less while awake (or that drops to this level during sleep for at least five minutes).

Many people receive in-home oxygen through an oxygen delivery device known as a nasal cannula. This thin, plastic tube has two small prongs at one end that rest in the nostrils. The nasal cannula can comfortably deliver oxygen to a person at one to six liters per minute (LPM), in concentrations ranging from 24 to 40 percent, depending upon how many LPM are being delivered. In comparison, room air contains about 21 percent oxygen, which is generally not enough for people with lung disease.

Do Mouth Breathers Get the Same Benefits of Supplemental Oxygen?

There are many benefits of long-term oxygen therapy, the greatest of which is that, when used at least 15 hours a day, it increases survival. But, are people who use oxygen and breathe through their mouths able to derive the full benefit of oxygen therapy? Or, does mouth breathing result in low levels of oxygen in the blood, cells, and tissues?

Research involving this topic is contradictory as demonstrated by the following examples:

  • In a study involving 323 mouth-breathing subjects, researchers set out to determine the effect of mouth breathing on oxygen saturation. For the purpose of the study, mouth breathing was assessed by physical examination and questionnaires filled out by subjects or their partners. Oxygen saturation was measured by pulse oximetry. Results of the study found that 34.6 percent of the people had normal oxygen saturation levels (95 percent or greater), 22.6 percent had an oxygen saturation level of 95 percent and 42.8 percent were considered hypoxic, with oxygen saturation levels below the set study limit of 95 percent. Researchers concluded that, while mouth breathing doesn't always result in hypoxia, it can contribute to it. 
  • Another study involving 10 healthy subjects compared aspirated gas samples of both open and closed-mouth breathers from the tip of a nasal cannula resting in the nasopharynx. The study concluded that not only did the delivered fraction of inspired oxygen (FIO2) increase with increasing oxygen flow rates but, compared to closed-mouth breathers, open-mouth breathers realized a significantly greater FIO2. However, in an editorial disputing the validity of the aforementioned study, Dr. Thomas Poulton, Chief Resident of the Bowman Gray School of Medicine's Department of Anesthesia, explains that gas samples taken from this area are not likely to be accurate because they contain only oxygen-enriched gas—not gas mixed with room air. Gas Samples taken from the trachea, which is further down the throat, would yield a more accurate gas concentration.

Much ADO About Mouth Breathing: What Can You Do About It?

The solution to mouth breathing is often dependent upon the underlying cause. Once accurately diagnosed, you can address treatment options which may include the following:

  • Clear your nasal passages - Some people have no choice but to breathe through their mouths because their nasal passages are blocked. A stuffy nose may be caused by allergies, illness, prior trauma or even weather changes. Over-the-counter antihistamines are available to keep allergy symptoms at bay and open up clogged nasal passages. Saline nasal spray is a natural alternative to medication and helps lubricate the nasal passages, often relieving congestion. If over-the-counter antihistamines and/or saline nasal sprays don't work for you, talk to your health care provider about using a prescription nasal spray such as Flonase.
  • Make an appointment with your dentist - Dentists are sometimes more knowledgeable than doctors when it comes to understanding mouth breathing. If your dentist determines that a facial or dental abnormality is the root of your mouth breathing, she may fit you with a functional device to help correct the problem.
  • Switch to a simple face mask - The easiest solution to mouth breathing, if medically appropriate, is to switch to a simple face mask. Generally, this is not very practical for many people and must first be approved by your oxygen-prescribing health care provider. One alternative is to consider using the nasal cannula during the day and switching to a simple face mask at night, so at least you'll be getting the full benefit of oxygen therapy during the hours in which you are asleep. Talk to your healthcare provider for more information about alternatives to the nasal cannula.
  • Nasal surgery - If your nasal passages are blocked because of a deviated septum, talking to an Ear, Nose, and Throat (ENT) Specialist about the surgery that may help correct the problem and allow you to breathe better. Remember, people with COPD should be especially cautious when undergoing surgery, because of the potential post-operative complications associated with anesthesia.
  • Transtracheal oxygen therapy - Transtracheal oxygen therapy (TTOT) is a method of administering supplemental oxygen directly into the trachea (windpipe). As an alternative to the nasal cannula, it delivers up to six liters of oxygen per minute through a small, plastic tube called a catheter. TTOT is generally reserved for people who have low blood oxygen levels that don't respond well to traditional methods of oxygen delivery.

The Importance of Pulse Oximetry for Those on Supplemental Oxygen

Whether you breathe through your mouth or nose, a pulse oximetry monitor is a must-have for anyone who receives in-home oxygen therapy. Pulse oximeters detect rapid changes in oxygen saturation levels providing you with a warning that you're low on oxygen. Compare prices on pulse oximetry monitors and never be in the dark about your oxygen saturation levels again.

Bottom Line on Mouth Breathing and Oxygen Therapy

There are some concerns about mouth breathing and supplemental oxygen therapy as outlined above, but the important point is that you are taking the time to research this topic and ask important questions—questions that the majority of people with lung disease are not asking.

We are learning that one of the most important factors in the quality of life and survival, not only with lung disease but with a multitude of health conditions, is being your own advocate in your health care. We have reached a point in medicine in which there is no single physician who can stay abreast of all of the new research and findings, even within a specific field such as pulmonology. At the same time, there are few people who are as motivated to find the answers to these questions than those who are coping with the diseases that prompt the questions.

Take the time to ask your physician the question you are seeking the answer to here. There are likely a number of different approaches that haven't necessarily yet been published but have been grappled with by those who face these concerns every day. Don't underestimate the respiratory technicians and therapists you work with either. These are the people who work with the nitty gritty of how supplemental oxygen gets to the people who need it along with the plethora of questions that arise.

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