Lung function decline is a defining characteristic of COPD, and it gets worse as the disease progresses. Because of this, most COPD patients eventually have to begin using supplemental oxygen to help their lungs once they become too weak to absorb enough oxygen on their own.
The purpose of supplemental oxygen is to deliver extremely oxygen-rich air to your lungs, usually using a pressurized oxygen tank or an oxygen concentrator. This air, generally about 85-95 percent pure oxygen, allows your lungs absorb more oxygen with every breath.
Supplemental oxygen is a very important part of COPD treatment because it helps your lungs take in enough oxygen to supply your organs and tissues with the oxygen they need. Without it, your blood oxygen saturation can fall to unhealthy levels—a condition called hypoxemia—which can lead to serious, life-threatening complications over time.