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Signs to Watch For That May Indicate You Need Oxygen
Chronic obstructive pulmonary disease (COPD) is progressive; with time, it leads to worsening airway restriction and reduced flow of air into the lungs. This means many people with COPD eventually develop hypoxemia, which when severe requires supplemental oxygen.
If you have COPD it can be difficult to know if you have hypoxemia. The signs of acute hypoxemia are similar to the normal symptoms of COPD: breathlessness, as well as increased breathing rate and breathing effort.
Chronic compensated hypoxemia can be just as hard to recognize. However, it is very important to recognize and treat because, in people with COPD, the consequences of chronic hypoxemia are very serious.
In COPD patients with chronic hypoxemia, the body compensates for low oxygen by constricting blood vessels in the unhealthy areas of the lungs to move blood to the healthier areas. However, if much of the lung is unhealthy, then most of the blood vessels in the lung will be constricted, making it hard for blood to flow through (termed pulmonary hypertension).
Blood normally flows from the body back to the right side of the heart, out to the lungs, back to the left side of the heart, and back out to the body. If many of the vessels in the lungs are constricted, this creates strong resistance for the right side of the heart to pump against.
As a result, the right side of the heart has to work harder and this can eventually lead to right-sided heart failure. One consequence of right-sided heart failure is a backlog of blood returning to the heart.
This causes increased blood pressure in the jugular vein (felt as a strong pulse in the neck) and liver and the slow return of blood from the lower limbs. Polycythemia also has consequences: it causes the blood to become thicker, which increases the risk of dangerous blood clots forming. Thus, oxygen therapy is important to prevent the longer-term consequences of hypoxemia.
However, not all COPD patients with hypoxemia require oxygen. Studies show that long-term continuous oxygen supplementation for people with severe hypoxemia even at rest prolongs life and reduces pulmonary hypertension. However, there is limited evidence that oxygen supplementation in COPD patients with mild to moderate hypoxemia prolongs life.
In fact, there are adverse consequences to giving oxygen when it is not needed. Too much oxygen tells your brain to slow breathing. This means less carbon dioxide is breathed off, which is also a dangerous scenario. People on long-term oxygen therapy need to be monitored regularly for this.
Hypoxemia is detected by a simple blood test that measures the pressure of oxygen in blood. Another method, although less reliable, is using a peg on the fingertip that measures the amount of red blood cells bound to oxygen.
The normal pressure of oxygen in blood is 80-100 mmHg and the hemoglobin-oxygen saturation should be 97 percent. Oxygen hits dangerously low levels when the pressure drops below 60 mmHg and the saturation below 90 percent.
Guidelines recommend starting long-term oxygen supplementation of at least 15 hours per day once blood oxygen pressure drops below 55 mmHg or saturation less than 88 percent. The aim of oxygen therapy is to maintain an oxygen pressure of at least 60 mmHg at rest and 90 percent saturation during exercise.
Thus, for people with COPD, the best method to determine if you need oxygen supplementation is to visit your medical practitioner regularly for tests. Other symptoms you can watch for at home include:
- Severe shortness of breath when exercising.
- Profound tiredness or weakness all the time.
- Confusion or thinking and memory difficulties.
- Waking out of breath during sleep.
- Cyanosis, or bluish discoloration of the lips and fingertips. This might initially occur during exertion or sleep but might persist at rest as hypoxemia worsens.
- Digital clubbing, which is a change in shape of the ends of the fingers.
- Resting home oxygen saturation readings less than 92 percent.
Signs of right-sided heart failure:
- A strong pulse in the neck.
- Bloating of the abdomen due to fluid in the abdomen or a large liver.
- Swelling of the legs.
Initially some COPD patients may only require oxygen for exercise or during sleep. Before prescribing oxygen, your blood oxygen levels may be measured during exercise or while sleeping to see if symptoms are due to hypoxemia and if supplemental oxygen helps. Eventually though, many COPD patients do require oxygen supplementation long-term.
However, being on oxygen doesn't mean a low quality of life — there are portable oxygen options out there that will allow you to stay active and on the go whenever possible.