Emphysema is a lung condition and a type of chronic obstructive pulmonary disease (COPD). Symptoms typically include shortness of breath, a persistent cough, and exercise intolerance. As it progresses, people with emphysema can have difficulty breathing even at rest.

Blood gas tests are a measurement of how much carbon dioxide and oxygen are in your blood. In people with emphysema, this measurement can be an indication of how far the condition has progressed.

A test called an arterial blood gas test is used to measure blood gas levels and is an important test for people with emphysema. This article will take a closer look at how emphysema affects blood gas, how it’s measured, and what blood gas results mean.

Blood gas tests measure the amount of oxygen and carbon dioxide in your blood. Every time you take a breath, the air travels through your windpipe, into your lungs, and then into thousands of small, thin tubes that end in clustered air sacs called alveoli.

Your blood vessels absorb oxygen through the walls of your alveoli and then deliver it, through your blood, to all the cells of your body. Carbon dioxide is removed from your bloodstream and out of your body when you exhale.

Emphysema damages the walls between the alveoli and the blood vessels. When this happens, your lungs can’t get as much oxygen into your bloodstream or remove as much carbon dioxide. This affects the levels of both oxygen and carbon dioxide in your blood.

People with mild to moderate emphysema often have standard blood gas levels. People with severe emphysema often have blood gas readings that indicate acidic blood, or higher levels of carbon dioxide in their blood. People with severe emphysema will also have reduced oxygen levels.

Abnormal or significantly changed arterial blood gas test results could be a sign that emphysema has caused significant damage to the alveoli walls. This often means that the condition is progressing.

An arterial blood gas test measures the levels of oxygen and carbon dioxide in your blood. It can be a little invasive, but this test provides detailed information about your blood gases as well as your blood’s pH balance.

It’s done by inserting a needle into an artery to collect blood. In many cases, an artery in your wrist is used. Only a small amount of blood is needed, but, because arteries lie deeper than veins, this test can be more painful than a standard blood draw.

It’s often used for people with emphysema and chronic bronchitis to test disease progression. The test can also help check kidney and metabolic function. It measures the amount of oxygen and carbon dioxide in your blood and checks how acidic or alkaline your blood is.

An arterial blood gas test takes three readings to get a picture of blood gas levels, which includes:

  • Hydrogen ion level: Readings between 7.35 and 7.45 are considered normal. The level of hydrogen ions is directly related to the amount of carbon dioxide in your blood. Readings below 7.35 indicate a high amount of carbon dioxide or acidic blood, while readings above 7.45 indicate an unusually low amount of carbon dioxide or alkaline blood.
  • Partial pressure of oxygen (PaO2) level: Readings below 75 mm Hg indicate low levels of oxygen.
  • Partial pressure of carbon dioxide (PaCO2) level: Readings between 35 mm Hg and 45 mm Hg are considered standard. Readings that are above 45 mm Hg indicate high carbon dioxide levels, while readings below 35 mm Hg indicate an unusually low amount of carbon dioxide.

Your blood gas levels are an indication of how well your lungs are moving oxygen into your blood and removing carbon dioxide from your body. With emphysema, arterial blood gas tests are often a good way to determine how the condition is progressing.

The acidity of your blood can also give doctors or healthcare professionals information about your metabolism or your kidney function. In some cases, blood gas levels can be a helpful indication regarding the extent of trauma or shock to the body.

Blood gas tests aren’t usually used to diagnose emphysema, but they’re very helpful for people with a known emphysema diagnosis. In early or mild emphysema, blood gas levels may be within an average range.

As the condition progresses, blood gas levels typically show indications of higher amounts of carbon dioxide. This tells doctors that the condition has progressed and that additional treatment may be needed.

As emphysema progresses, you may experience more symptoms such as:

  • shortness of breath even while at rest
  • coughing
  • wheezing
  • exercise intolerance
  • a “barreled” chest, with the distance between a person’s back and chest wall increasing in a noticeable way
  • breathing through pursed or tightly pressed lips

Effectively treating emphysema can improve blood gas levels and reduce symptoms. The right treatments will depend on your overall health, other medications you’re taking, and the type of treatment plan you and a doctor believe is right for you.

Treatment options include:

  • Bronchodilators: These inhaled medications help open up your airways.
  • Steroid medication: Steroids help reduce inflammation. You can take them through an inhaler or orally.
  • Pulmonary rehabilitation: A pulmonary rehabilitation program can teach you breathing exercises that may help improve your breathing and increase your exercise tolerance.
  • Diet: Maintaining a moderate weight can sometimes help improve breathing and blood gas levels. In the later stages of emphysema, you might need to gain weight. A doctor or a registered dietitian can help you establish the best nutrition plan for you.
  • Oxygen therapy: Oxygen therapy involves a type of supplemental at-home oxygen device that a person with emphysema can connect to regularly. Oxygen therapy can increase the amount of oxygen that’s inhaled and gets into the bloodstream. Often, blood gas readings can indicate when someone with emphysema needs oxygen therapy.
  • Lung surgery: In some cases, a surgery called lung volume reduction surgery can remove damaged lung tissue. This can help the lungs work better and may improve blood gas levels.
  • Lung transplant: A lung transplant can help people with advanced emphysema regain lung function.

Emphysema is a lung condition that makes it difficult for proper gas exchange to happen in the body. Blood gas tests can measure the oxygen and carbon dioxide levels in your blood, which are important metrics for someone with emphysema. An arterial blood gas test measures these levels and can be an indication of how emphysema is progressing.

People with mild to moderate emphysema generally have blood gas readings that fall within a standard range. However, if emphysema progresses, blood gas levels typically fall outside the standard range. Specifically, there may be higher amounts of carbon dioxide in the blood.

Regular monitoring of blood gas levels can help doctors determine when emphysema has progressed and if additional treatment is needed.