Pulmonary hypertension associated hypoxemia

Hypoxemia, with or without respiratory acidosis may be the most important factor cause secondary pulmonary hypertension.

What is hypoxemia? Hypoxemia is defined as an oxygen tension in arterial blood that is below normal. Hypoxemia usually leads to hypoxia, a decrease in oxygen supply to the tissue, which can also be caused by problem outside the respiratory system.  

Hypoxemia, caused by alveolar hypoventilation, vascular obstruction primary cardiac disease and conditions causing acquired cardiac disease.

Alveolar hypoventilation can result from diseases caused by alveolar destruction or from disorders that prevent the chest wall from expanding sufficiently to allow air into the alveoli.

Hypoxemia resulting from this ventilation-perfusion mismatch also causes vasoconstriction, furthermore increasing vascular resistance and resulting in pulmonary hypertension.

Hypoxemia may cause an increase in ventilation and cardiac output as the body compensates. By increasing the oxygen content of the arterial blood, the muscle requirements of the pulmonary and cardiovascular systems are reduced.
Pulmonary hypertension associated with lung disease and/or hypoxemia