The drive to breathe is normally your bodys detection of high Carbon dioxide levels. With COPD, the lungs retain more CO2 than normal and cancels the normal way of breathing. With COPD patients the hypoxic drive is activated and becomes the primary way of breathing. It is triggered when the body detects low concentrations of oxygen. Therefore, if a COPD patient gets too much oxygen, the hypoxic drive will shut off and the patient will lose the sense to take a breath. This is in reply to Dr. Sanderson from Mayo Clinic.