COPD is a disease of airflow obstruction. It can be caused by chronic bronchitis and emphysema. Most of the people with COPD have an extensive cigarette smoking history. Patients are eligible for oxygen therapy at home if their room air resting ABG shows an SaO2 less than 88% or a PaO2 less than 55 mm Hg. With a PaO2 of 56-59 mm Hg or a SaO2 less than 89%, people who have polycythemia, heart failure or pulmonary hypertension can receive oxygen therapy. Oxygen therapy as a treatment for COPD has been shown to reduce mortality and morbidity.
The Washington Manual of Medical Therapeutics, 31st edition.