Supplementary oxygen is sometimes prescribed for PH patients when a patient has hypoxemia (an inadequate amount of available oxygen in the blood) at rest or with physical activity. Patients are considered hypoxic if their oxygen saturation levels are consistently under 88%. Unless patients with PH have an underlying hypoxic lung disease their normal oxygen saturation levels are usually above 88%.

Supplementary oxygen, however, is an important addition to treating the symptoms of a PH patient with hypoxemia or under special conditions, such as when hospitalized with a respiratory infection, or at high altitudes or sometimes when traveling by air.

For information about oxygen therapy in general, see The American Association for Respiratory Care, Home Oxygen Therapy and the National Home Oxygen Patients Association