What Is Anemic Hypoxia?

Anemic hypoxia is oxygen deprivation in the tissues of the body caused by a decline in the blood’s ability to carry oxygen. This can be caused by a number of factors including true anemia, where the number of red blood cells drops, making it harder for the blood to supply the body with the oxygen it needs. Patients with this condition may initially appear well, but start to develop fatigue, air hunger, and confusion as the limited oxygen supply persists and affects the brain. Prompt treatment is necessary to prevent permanent damage or death.

In patients with anemia, the reduced number of red blood cells limits the amount of oxygen the blood can transport. Although gas exchange in the lungs is normal, as the lungs trade carbon dioxide from the cells for fresh oxygen from the air, there aren’t enough red blood cells in circulation to meet the body’s needs. The result is anemic hypoxia, which can be observed in cases of both acute and chronic anemia. Patients may need transfusions as well as other treatment to address the underlying cause of the anemia.

Another potential cause of this condition is carbon monoxide poisoning. In patients who have inhaled carbon monoxide, the chemical binds to the receptors that normally carry oxygen, effectively locking the oxygen out of the red blood cells. As the blood circulates through the body, it has the normal amount of red blood cells, but they carry carbon monoxide instead. Over time, the patient’s tissues become oxygen-starved, leading to anemic hypoxia.

Some medications, particularly nitrates, can also cause this condition. They change the receptors on the red blood cells so they cannot carry oxygen as efficiently. As in carbon monoxide poisoning, the patient has red blood cells available, but they are effectively useless because they can’t carry the necessary oxygen. This is a known complication of some drug therapies and patients may be monitored for signs and symptoms to determine if they need treatment.

When a patient demonstrates signs of anemic hypoxia, or any form of oxygen deprivation, medical providers may administer oxygen and take other measures to immediately stabilize the patient. They also collect a medical history and conduct tests to find out why the patient isn’t getting enough oxygen. This information can help them determine on the best course of treatment. For example, if the patient has a bone marrow disease that is destroying red blood cells and limiting the oxygen-carrying capacity of the blood, that disease needs to be treated or controlled to resolve the anemic hypoxia.