Why Is Supplemental Oxygen Beneficial?
Some people in this community utilize home oxygen therapy. It benefits them by keeping oxygen levels normal. Today I would like to answer the question: “Why is home oxygen so beneficial for COPD?” Why do we need it? Here is what to know.
For most of history, people with low oxygen levels went undiagnosed. And, prior to our modern era, people with low oxygen levels did not have access to supplemental oxygen. So, let us assume your oxygen levels are low and it goes untreated over a long period of time. What happens to your body?
What happens due to low oxygen levels?
COPD has two components. One is chronic bronchitis. This is where airways become chronically inflamed and obstructed. The second is emphysema. This causes the breakdown of lung tissue. Together, they create areas of your lungs that are poorly ventilated. This means these areas don’t receive much oxygen.
Hypoxemia
This means you have a lower than normal level of oxygen in your arterial blood. It means less oxygen is getting from your lungs to your arterial blood. With COPD, blood oxygen levels drop gradually over time. And, when this goes on long-term, your body will gradually adapt to low oxygen levels by attempting to make changes to increase the oxygen supply.1
Hypoxia
This is when less oxygen than normal gets to your tissues and is a result of hypoxemia. Less oxygen in your blood means less oxygen is getting to your tissues.
Vasodilation
So, your body thinks it can get more oxygen by speeding up the flow of blood. So, it dilates peripheral blood vessels. This increases your heart rate and force. Your heart beats harder and faster. Your blood pressure increases. More blood moves through your lungs. But, unfortunately, this does not bring more oxygen. The problem persists.2
Hyperpnea
This is an increased respiratory rate. Your body thinks it can draw more oxygen into your lungs by making you breathe faster. It thinks that if you inhale more you will be sucking more oxygen molecules into your lungs. But, this doesn’t work either. So, unfortunately, this also doesn’t remedy the problem.2
Pulmonary Vasoconstriction
So, think of all the areas of your lungs that are poorly ventilated and do not receive much oxygen. After a long time trying the previously mentioned methods, your body takes the next step of constricting blood vessels feeding these poorly ventilated areas. This shunts oxygenated blood away from these poorly ventilated areas. It shunts it towards areas that are well ventilated. This helps to keep your arterial oxygen levels normal or close to normal. Or, at least this is the goal.3-4
Over time, more and more of these diseased areas develop and your heart has to work extra hard to pump blood through these narrow blood vessels. This eventually leads to another complication called pulmonary hypertension.2
Secondary Polycythemia
This means that you develop an abnormally large number of red blood cells. Secondary means that it is secondary to a COPD diagnosis. It’s secondary to hypoxemia.2
Why does this happen? It’s because your liver senses that oxygen levels are low. So, it secretes a protein called erythropoietin. This is a hormone that tells your bone marrow to increase the supply of red blood cells. These are cells that have hemoglobin molecules on them. Hemoglobin carries oxygen through your blood.2,5
Think of your arterial blood as a train. Each hemoglobin molecule is a seat on that train. Oxygen molecules represent passengers. Your body thinks that making more seats on the train will allow the train to carry more passengers or the amount of oxygen getting to blood will be the same.
With more seats on the train, this makes the blood is thicker than normal. Your heart has to work harder to pump it through your lungs which can lead to another complication called pulmonary hypertension.2
Pulmonary Hypertension
As described above, this may be a secondary result of both vasoconstriction and polycythemia. The heart has to work extra hard to pump thick blood through narrowed arteries which causes the pulmonary blood pressure to be abnormally high.4
Cor pulmonale
This is a fancy term for right heart failure due to COPD. It means that your right heart has become abnormally large (hypertrophied) due to years of working hard to pump blood through diseased lungs. I describe this in more detail in my post Links Between COPD and Heart Failure.6
So, how does oxygen help?
Studies show that home oxygen therapy has many benefits. The main benefit is to keep oxygen levels in the normal range. This works to help prevent the feeling of shortness of breath. Although, studies also show that home oxygen also prevents your genes from secreting chemicals that cause the secondary complications of hypoxia as described above.1-2
Today, over 800,000 people in the U.S. with lung diseases like COPD use home oxygen therapy. This has helped many people with COPD live longer and better despite their diagnosis and now you know why.2
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