How Does COPD Affect Breathing?

This article was written by Stephanie Williams, BS, RRT.

When people are newly diagnosed with chronic obstructive pulmonary disease (COPD), they have lots of questions about what COPD is, what it means, and how it affects the lungs. Let’s take a few minutes to explore what COPD means and the difference between chronic bronchitis and emphysema. As you read, it is important to remember that many people living with COPD have features of both chronic bronchitis and emphysema. That is why we prefer to use the umbrella term chronic obstructive pulmonary disease.

Here we see a cartoon illustration of the tiny, delicate lung tissue called alveoli. Each individual image shows two alveoli. In healthy lungs, there are hundreds of millions of these tiny air sacs, or alveoli. In this illustration, you can also see a small segment of airways leading into the alveoli. These segments of the lung are microscopic in size. The one on the left is normal tissue, bronchitis is in the middle, and emphysema is on the right.

When the lungs become exposed to irritants, pollution, smoke, etc., different parts of the lung can be injured. The main difference between chronic bronchitis and emphysema is the location of this injury or damage in the lung. Chronic bronchitis affects the airways (breathing tubes), and emphysema affects the alveoli.

In normal airways, you can see good expansion and contraction of the alveoli. The airways are large and clear. Air is flowing freely. They are not congested with mucus. Inside these alveoli is a very thin membrane, called the acinus, is rich in capillary blood flow. These air sacs are where the exchange of oxygen and carbon dioxide takes place during breathing. Oxygen enters the blood vessels and carbon dioxide, the waste product of our cells, passively enters into the alveoli from the capillaries to be exhaled. The acinus allows an alveolus to have multiple units of gas exchange. In this picture, we observe 14 functional units within two alveoli.

Now, let’s talk about chronic bronchitis. The airways swell and become congested with mucus. In advanced stages of COPD lung tissue loses elastic qualities and become stiffer. There is less expansion and contraction in the picture. Chronic bronchitis does not impact the alveoli, so gas exchange is normal. Breathing medicines like bronchodilators and inhaled steroids work only on the airways. They do not work on injury inside the alveoli.

What about emphysema? The airways are free of mucous and swelling, but inside the alveoli, acinus are destroyed and alveoli become floppy because damage has occurred to the elastic tissue of the lung. Now, instead of having 14 functional units of gas exchange there are only two. This leads to an inefficient respiratory system. What is the drug of choice for people with emphysema? Oxygen. As emphysema advances some people may be required to wear oxygen. Some of you may be wondering, “Do all patients with emphysema need oxygen?” The answer is no. Some people use oxygen and others do not. Testing can be done to determine if a person would benefit from supplemental oxygen.

By understanding how chronic bronchitis and emphysema affect the lungs differently, you can learn how to better manage your lung disease. These differences help explain why people have different symptoms and why different medications are needed to help treat COPD. It is good to ask your healthcare team specific questions about your COPD diagnosis to learn if you have chronic bronchitis, emphysema, or a combination of the two. Having this information can make a big difference in how well you live with COPD. Visit our downloads library to find more information about COPD.