An estimated 30 million people in the United States have chronic obstructive pulmonary disease (COPD), according to the COPD Foundation.
COPD is caused by obstructions to a person's airflow, where oxygen doesn't move well through their lungs. Over time, the lungs become inflamed and damaged.
Causes of hypoxia and hypoxemia
Because a person needs oxygen to survive, COPD can have harmful effects on the body. Two disorders that a person with COPD can develop are hypoxia and hypoxemia.
Shortness of breath and frequent coughing may indicate COPD-related hypoxia.
Hypoxia and hypoxemia are important terms to know in connection with COPD because their progression can ultimately lead to disability and death.
Oxygen passes from the lung tissue to the blood via the alveoli, or air sacs. Ideally, oxygenated blood leaves the lungs and travels to the other tissues in the body. The body, especially the brain and heart, needs sufficient amounts of oxygen to survive.
COPD damages the lungs, and if they get seriously damaged, a person may develop hypoxia. Hypoxia occurs when the blood does not deliver enough oxygen to the air sacs in the lungs.
The body can adapt in certain ways in order to cope with lower than normal oxygen levels. However, in the case of COPD, hypoxia in the lungs can cause hypoxemia in the body.
Hypoxemia occurs when oxygen levels in the blood become so low that tissues and organs in the body don't get the oxygen they need. This happens because COPD damages the air sacs, which means the lungs cannot transfer the available oxygen to the bloodstream.
Hypoxemia is harmful because organs, such as the heart and the brain, that are particularly sensitive to changes in oxygen levels can become injured or damaged.
Symptoms and complications
Feeling short of breath and having difficulty catching one's breath can indicate that a person is experiencing hypoxia. People with COPD-related hypoxia may experience the following symptoms:
- coughing frequently
- feeling as if one is choking because they are short of breath
- less ability to tolerate physical activity
- rapid breathing
- waking up in the middle of the night without being able to catch their breath
Hypoxia and hypoxemia can also lead to other conditions including:
When a person has difficulty getting enough oxygen through the body, the brain can become affected. In low oxygen states, a person may experience injury to nerve cells and changes in function of the brain.
Low oxygen levels as a result of COPD can also lead to fewer neurotransmitters, the chemical messengers of the brain, being created. Creating these neurotransmitters often requires oxygen in order to work properly.
The right side of the heart pumps blood that is low in oxygen to the lungs. Once in the lungs, blood can pick up oxygen again from the air that has been breathed in. The oxygenated blood then returns to the left side of the heart where it is pumped throughout the body.
A person with COPD can experience inflammation in the pulmonary arteries that transfer blood from the right side of the heart to the lungs. This inflammation can cause high pressures to build up in the lungs. This higher pressure means that the right side of the heart has to work harder to pump blood through those arteries. If this continues, the heart can become damaged and weakened.
Secondary polycythemia is the body's response to chronic hypoxia from COPD. The body starts creating extra red blood cells to help carry more oxygen.
When extra blood cells are made the blood is more prone to clotting. In COPD, this condition can also increase the risk of abnormal heart rhythms, cause longer hospital stays, and lead to more breathing complications.
Skeletal muscle dysfunction
People whose COPD has reached a more advanced stage can have difficulty engaging in physical exercise and activity. As a result, their muscles start to become weaker. The weakened muscles are more easily fatigued, making it even harder for a person with COPD to exercise.
The chronic lack of oxygen can cause inflammation in the body's tissues, which can lead to a number of conditions.
The best treatments for COPD-related hypoxia and hypoxemia are those that keep the airways open and reduce inflammation. Preventing infections that can worsen lung function can also help.
Bronchodilator therapy may help to alleviate COPD hypoxia by improving oxygen flow.
Examples of management for COPD hypoxia and hypoxemia include:
- Bronchodilator therapy: These are typically inhaled medications that reduce the spasm and tightening of the smooth muscle in the airways to improve oxygen flow.
- Immunizations: Getting a regular flu shot and scheduled pneumonia and pertussis (whooping cough) vaccines can help a person prevent infections that could make lung hypoxia and COPD worse.
- Oral or inhaled corticosteroids: These medications reduce inflammation in the airways and in the body during a COPD flare. Examples include beclomethasone and prednisone.
- Quitting smoking: If a person with COPD smokes, quitting smoking can have significant benefits in treating the condition and reducing its symptoms. Quitting also boosts the immune system.
- Pulmonary rehabilitation therapy: This treatment involves breathing "retraining" to teach a person the best ways to breathe when their lungs are impaired. It also slows the decline of lung function and increases a person's ability to exercise.
Along with nutritional counseling, pulmonary rehabilitation therapy can help a person with COPD breathe better.
If a person has severe hypoxemia due to COPD, a doctor will commonly recommend oxygen therapy. This involves breathing in extra oxygen through a small, flexible tube that fits in the nostrils known as a nasal cannula.
According to an article in the International Journal of Chronic Obstructive Pulmonary Diseases, long-term oxygen therapy may improve quality of life in patients with COPD hypoxemia by decreasing COPD flares and increasing tolerance to physical activity.
Current studies show that individuals with severe COPD are likely to benefit the most from oxygen treatment. However, not everyone with COPD is a good candidate for supplemental oxygen. It is very important that a doctor carefully prescribes and closely monitors oxygen therapy, as too much oxygen can lead to higher carbon dioxide levels.
Although exercise can be difficult to accomplish when a person has COPD, exercise can improve the oxygen uptake in the lungs of a person with mild COPD and improve their breathing patterns. However, those in more advanced stages of COPD may have difficulty with any amount of physical activity.
COPD is a progressive condition, which means it gets worse as time goes on. COPD also causes airflow difficulties that cannot be fully reversed, even with medications and treatments. This is especially true if smoking was a key factor in developing COPD and a person continues to smoke.
There are several key factors that affect the outlook for a person with COPD.
Body mass index and age may affect the outlook for a person with COPD.
- body mass index
- how often a person experiences COPD flares
- how short of breath a person is with activity
- level of hypoxemia
- pulmonary artery pressures
- pulmonary function test results
- resting heart rate
- smoking status
- other health conditions not related to the lungs
The more often a person requires hospitalization with COPD, the poorer their health outlook tends to be. According to the Cleveland Clinic, of more than 1,000 patients admitted to the hospital with respiratory failure and raised carbon dioxide levels in the blood, 89 percent survived the hospitalization, but only about a half of these people were still alive after 2 years.
However, some people have more stable COPD and can live for a long time with the condition. The best outcomes are related to good follow-up with doctors, taking all prescribed medications as directed, and living a healthful and fit lifestyle.