About Pulmonary Hypertension: Pulmonary hypertension is usually caused by a narrowing of the small arteries of the lung, which makes it hard for blood to flow. Blood pressure increases. The right side of the heart must work harder to pump blood, and may become enlarged over time. Eventually, heart failure may develop.
If breathing becomes too labored for a pulmonary hypertension patient and the level of oxygen in their blood becomes too low, they may be advised to begin oxygen therapy. MORE: How pulmonary hypertension is managed. Doctors can prescribe oxygen therapy for when the patient most needs it, usually during exercise or while sleeping.