Chronic obstructive pulmonary disease, commonly known as COPD, is a term used to refer to a group of progressive lung diseases. The most common of these lung diseases are chronic bronchitis and emphysema, and many people with COPD have both these conditions. We all know that the lungs are critical for providing our body with fresh oxygen while also ridding it of carbon dioxide. This essential process is known as gas exchange. In many people, especially those with chronic obstructive pulmonary disease, the process of gas exchange can get impaired. When this happens, it becomes challenging for the body to get enough oxygen to support day-to-day activities and remove enough carbon dioxide, a condition known as hypercapnia. Read on to find out about what it means to have COPD with impaired gas exchange.
Understanding Chronic Obstructive Pulmonary Disease
Chronic obstructive pulmonary disease (COPD) is a group of lung conditions like chronic bronchitis and emphysema that make it difficult for a person to breathe. These conditions are progressive in nature, which means that they tend to worsen over time. Emphysema and chronic bronchitis are two of the most common conditions that come under COPD. These conditions affect the lungs in different ways. In emphysema, the small air sacs in the lungs, known as alveoli, get damaged, while chronic bronchitis involves long-term inflammation of the airways.(1, 2, 3, 4)
According to the Centers for Disease Control and Prevention (CDC), nearly 15.7 million people in the United States, or nearly 6.4% of the country’s population, have COPD. This made COPD the fourth leading cause of death in the United States in 2018.(5, 6)
Understanding the Process of Gas Exchange in the Lungs
Gas exchange is the critical process in the body where carbon dioxide, which is a waste gas, gets exchanged in the lungs for fresh oxygen. Here’s how the process of gas exchange works:(7, 8)
- When you breathe in, the lungs expand, and air enters through the nose and mouth.
- The air you breathe in travels through the airways that gradually start to get smaller until the air reaches the alveoli. Alveoli are the tiny air sacs present in your lungs where the process of gas exchange takes place.
- Oxygen from the air you take in then moves through the walls of the alveoli and enters into your bloodstream through the tiny blood vessels known as capillaries.
- At the same time as the oxygen is moving into the bloodstream, the waste gas carbon dioxide moves from the bloodstream into the alveoli.
So when you exhale or breathe out, the lungs deflate, pushing out the carbon dioxide and up through the airways where it exits the body through your nose and mouth.
The flexibility and health of your alveoli and airways are critical in ensuring effective gas exchange in the lungs. However, in people with chronic obstructive pulmonary disease, these structures get damaged. Because of this, the process of gas exchange is not able to occur as efficiently as it should.(9, 10)
Some of the mechanisms behind impaired gas exchange in people with the chronic obstructive pulmonary disease can include one or a combination of the following:
- Walls of the alveoli that have gotten destroyed, leading to a decreased surface area for gas exchange.
- Alveoli or airways that have lost elasticity due to COPD and are unable to expand and deflate on their own to their full capacity when you breathe in and out.
- Airways that have gotten clogged with thick mucus.
- Long-term inflammation that has caused thickening of the airway walls.
Symptoms of Impaired Gas Exchange and COPD
When the process of gas exchange is impaired, you cannot effectively get enough oxygen or rid the body of carbon dioxide. This can cause a wide variety of symptoms, including:
- Shortness of breath, especially when exerting yourself
- Nasal flaring
- Feeling fatigued or tired
- Abnormal breathing rate
- Quick heart rate
- A headache on waking up
- Feeling irritable or restless
- State of confusion
- Skin that is gray, pale, or blue in color
Impaired gas exchange is also characterized by hypercapnia and hypoxemia. Hypoxemia is a condition marked by a lower level of oxygen in the blood, while hypercapnia is a condition in which there is excess carbon dioxide present in the bloodstream.(11, 12)
Causes of Impaired Gas Exchange in People with COPD
Chronic obstructive pulmonary disease, and the impaired gas exchange associated with this condition, are caused by many reasons, one of which is long-term exposure to environmental irritants. When you breathe in, these irritants enter your body and, over a long period of time, can cause damage to your lung tissue. Cigarette smoking is one of the most common irritants that cause COPD.(13, 14, 15) Other irritants may include:
- Cigar, pipe, and other types of tobacco smoke
- Secondhand smoke
- Chemical fumes
- Air pollution
How to Diagnose Impaired Gas Exchange and COPD?
There are several diagnostic tests that can help detect and diagnose impaired gas exchange in people with chronic obstructive pulmonary disease. There are two main methods of detecting impaired gas exchange. These include:
- Pulse Oximetry: This is a non-invasive test in which a light clip-like device is attached to your finger. The test measures the amount of oxygen present in your bloodstream.(16)
- Arterial Blood Gas Analysis (ABG): This is a blood test that measures oxygen and carbon dioxide levels in the bloodstream.(17)
Apart from these two tests, in some rare cases, your doctor may also perform pulmonary ventilation or perfusion scan (VQ scan) to compare the airflow in your lungs to the amount of oxygen in the bloodstream.(18)
Is There a Treatment for Impaired Gas Exchange and COPD?
Impaired gas exchange is usually treated with the use of supplemental oxygen. Supplemental oxygen helps counteract the effects of hypoxemia as oxygen is directly delivered to your lungs. You will breathe in supplemental oxygen through a mask or a nasal cannula.(19)
Depending on the severity of your symptoms, you might need to take supplemental oxygen either all the time or only at certain times. Oxygen therapy has to be monitored carefully as, in some cases, it can worsen hypercapnia. Treatment for hypercapnia includes non-invasive ventilation therapy, usually known as BiPAP, which is the name of the brand of ventilation therapy machine. During the process of BiPAP, you have to wear a mask that provides a continuous flow of air into the lungs, creating positive pressure. This helps the lungs expand and remain expanded for a more extended period of time.(20)
Some of the other types of treatments for a chronic obstructive pulmonary disease that might be recommended include:
- Lifestyle Changes: If you smoke, your doctor will recommend that you quit smoking. They will also recommend that you avoid other irritants like air pollution and secondhand smoke.
- Bronchodilators: bronchodilators are drugs that help open up your airways, which makes it easier to breathe. These are usually administered by an inhaler. In some cases, a bronchodilator may be combined with a steroid.(21)
- Pulmonary Rehabilitation: Pulmonary rehabilitation can teach you strategies on how you should go about your daily chores when you have COPD. You will learn breathing techniques, exercise plans, and counseling.
- Vaccines: In people with COPD, contracting a lung infection can make their condition worse. Due to this, your doctor may recommend that you should remain updated on your flu, pneumococcal, and COVID-19 vaccines.
- Surgery: Surgeries are typically only recommended for people who have severe COPD. Some of the surgical options may include bullectomy, lung volume reduction, and lung transplant.
Your doctor will work with you to come up with a treatment plan for your impaired gas exchange and chronic obstructive pulmonary disease.
COPD with impaired gas exchange is linked with hypoxemia. Having other health conditions like heart disease, lung cancer, and pulmonary hypertension can lead to a poorer COPD outlook and impaired gas exchange. The treatment for COPD with impaired gas exchange revolves around reducing the symptoms and slowing down the disease progression. In order to reduce the risk of complications from the disease and improve your outlook, it is important that you listen to your doctor and stick to your COPD treatment plan.
- Barnes, P.J., Shapiro, S.D. and Pauwels, R.A., 2003. Chronic obstructive pulmonary disease: molecular and cellularmechanisms. European Respiratory Journal, 22(4), pp.672-688.
- Agusti, A.G.N., Noguera, A., Sauleda, J., Sala, E., Pons, J. and Busquets, X., 2003. Systemic effects of chronic obstructive pulmonary disease. European Respiratory Journal, 21(2), pp.347-360.
- Anthonisen, N.R., Wright, E.C., Hodgkin, J.E. and IPPB Trial Group, 1986. Prognosis in chronic obstructive pulmonary disease. American Review of Respiratory Disease, 133(1), pp.14-20.
- Anto, J.M., Vermeire, P., Vestbo, J. and Sunyer, J., 2001. Epidemiology of chronic obstructive pulmonary disease. European Respiratory Journal, 17(5), pp.982-994.
- Cdc.gov. 2021. CDC – Basics About COPD – Chronic Obstructive Pulmonary Disease (COPD). [online] Available at: <https://www.cdc.gov/copd/basics-about.html> [Accessed 16 December 2021].
- Rycroft, C.E., Heyes, A., Lanza, L. and Becker, K., 2012. Epidemiology of chronic obstructive pulmonary disease: a literature review. International journal of chronic obstructive pulmonary disease, 7, p.457.
- Ben-Tal, A., 2006. Simplified models for gas exchange in the human lungs. Journal of theoretical biology, 238(2), pp.474-495.
- Schittny, J.C., 2017. Development of the lung. Cell and tissue research, 367(3), pp.427-444.
- Hsia, C.C., Hyde, D.M. and Weibel, E.R., 2016. Lung structure and the intrinsic challenges of gas exchange. Comprehensive physiology, 6(2), p.827.
- Wagner, P.D., 2008. Pulmonary gas exchange. An Introductory Text To Bioengineering, pp.181-207.
- Kent, B.D., Mitchell, P.D. and McNicholas, W.T., 2011. Hypoxemia in patients with COPD: cause, effects, and disease progression. International journal of chronic obstructive pulmonary disease, 6, p.199.
- Abdo, W.F. and Heunks, L.M., 2012. Oxygen-induced hypercapnia in COPD: myths and facts. Critical Care, 16(5), pp.1-4.
- Zuo, L., He, F., Sergakis, G.G., Koozehchian, M.S., Stimpfl, J.N., Rong, Y., Diaz, P.T. and Best, T.M., 2014. Interrelated role of cigarette smoking, oxidative stress, and immune response in COPD and corresponding treatments. American Journal of Physiology-Lung Cellular and Molecular Physiology, 307(3), pp.L205-L218.
- Davis, R.M. and Novotny, T.E., 1989. The epidemiology of cigarette smoking and its impact on chronic obstructive pulmonary disease. American review of respiratory disease, 140(3_pt_2), pp.S82-S84.
- Rom, O., Avezov, K., Aizenbud, D. and Reznick, A.Z., 2013. Cigarette smoking and inflammation revisited. Respiratory physiology & neurobiology, 187(1), pp.5-10.
- Schermer, T., Leenders, J., in’t Veen, H., van den Bosch, W., Wissink, A., Smeele, I. and Chavannes, N., 2009. Pulse oximetry in family practice: indications and clinical observations in patients with COPD. Family practice, 26(6), pp.524-531.
- Emerman, C.L., Connors, A.F., Lukens, T.W., Effron, D. and May, M.E., 1989. Relationship between arterial blood gases and spirometry in acute exacerbations of chronic obstructive pulmonary disease. Annals of emergency medicine, 18(5), pp.523-527.
- Moua, T. and Wood, K., 2008. COPD and PE: a clinical dilemma. International journal of chronic obstructive pulmonary disease, 3(2), p.277.
- Long-Term Oxygen Treatment Trial Research Group, 2016. A randomized trial of long-term oxygen for COPD with moderate desaturation. New England Journal of Medicine, 375(17), pp.1617-1627.
- Carlucci, A., Delmastro, M., Rubini, F., Fracchia, C. and Nava, S., 2003. Changes in the practice of non-invasive ventilation in treating COPD patients over 8 years. Intensive care medicine, 29(3), pp.419-425.
- Tashkin, D.P., Celli, B., Decramer, M., Liu, D., Burkhart, D., Cassino, C. and Kesten, S., 2008. Bronchodilator responsiveness in patients with COPD. European Respiratory Journal, 31(4), pp.742-750.
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