Oxygen Therapy in COPD and Evidence to be Collected
Posted Sep 15 2010 5:48am
COPD and decreased Oxygen
Decrease in levels of Oxygen in blood is an important consequence of COPD. Compromising the air flow in the lungs leads to diminished blood Oxygen. The amount of Oxygen in blood is taken from arterial blood levels with samples (Presure of Oxygen gas) or with devices using infrared readings (Saturation by Oxymeter). Presure of the Oxygen Gas in arterial blood is symbolized by PaO2.
Terms related to diminished Oxygen
Decreased PaO2 (also called hypoxemia) has different presentations and severity in COPD. It can be continuous, dis-continuous. The non-continuous for of hypoxemia makes of it manifested during exercise (from activities of daily living to strenuous physical exercise) or during rest (day or nocturnal which can be during sleep or just lying down). The severity of hypoxemia can go from mild to severe.
Benefits of Oxygen Therapy
he subset of patients with COPD who develop severe hypoxemia has shown to improve their survival with Oxygen therapy. Oxygen therapy can be short-term (including bursts or as needed) or long-term. Long-term Oxygen therapy (LTOT) has been under assessment since it is costly and uncomfortable for patients. LTOT has shown to be clearly beneficial for patients with COPD and severe resting hypoxemia. However, it is still work in progress to define the benefit of LTOT for patients with non-severe hypoxemia at rest or during exercise in terms of survival.
For patients with hypoxemia during exercise (or perhaps at the end of it), Oxygen Therapy has shown to enhance the exercise performance. In patients who show hypoxemia during nights, the benefits are not clear yet.
Deciding Oxygen Therapy Use
Discussing hypoxemia with doctors implies reading of results. Severe and very severe COPD is a special field since the disease can be more complicated and the use of LTOT adds some difficulty in the management of the patient. The difficulty is in fact associated with other gases in blood (like CO2) which can be affected if higher amounts of Oxygen are administered. This situation requires close follow up to avoid additional complications.
Deciding with your doctor when to use LTOT is an important part of the conversation which may lead to use or delay of Oxygen Therapy. Oxygen is not a solution for COPD but an element to help patients to cope with a consequence of the disease. This consequence leads to impaired extra-pulmonary functions that can make the patient feel worse. Use of Oxygen therapy requires a careful assessment and not a pure simple decision based on the breathlessness.