Hypoxemia is abnormally low oxygen in blood. Specifically, it is oxygen deficiency in arterial blood.

• Respiratory disorders, often, including:
  • Ventilation (i.e. rate/volume of air entering the lungs), including:
    • Hypoventilation
  • Perfusion (i.e. transfer of air from the lungs to the blood)
• Cardiovascular causes, e.g. shunts

• Can cause tissue hypoxia, as blood is not supplying enough oxygen to the body