What Is Ischemic Hypoxia?

Ischemic hypoxia is a condition caused by the diminished availability of oxygen-rich blood to body. It is the result of overall slower circulation of blood through the tissues, leading to the smallest parts of the blood vessels, the capillaries, having less tension by which to force oxygen into the target body tissues. Ischemic hypoxia can be present even though the saturation of the blood and overall amount of the blood circulating in the body is normal. The condition can lead to irreparable damage to important tissues, like those in the brain and the heart. Tissues in the limbs can suffer from significant ischemic hypoxia as well.

Serious ischemic hypoxia often occurs in the fetal environment. Called, intrapartum hypoxia or hypoxic ischemic encephalopathy (HIE), it refers to the brain not receiving enough oxygen because of a malfunction in the circulatory system. If the mother is injured while pregnant, the fetus may not receive enough oxygen in utero, possibly leading to brain damage. Most commonly, the condition is seen while the mother is giving birth when there is a complication with the umbilical cord being wrapped around the baby’s neck or “pinched.” HIE has the potenential to be fatal or cause intellectual disability, seizures, or cerebral palsy.

Ischemic hypoxia is also present in ischemic cardiomyopathy, sometimes called coronary artery disease. Narrowing of the blood vessels by a hard substance called plaque causes the body to become less able to carry enough blood for the heart to function properly. The heart becomes weaker as the disease progresses, leading to more circulatory dysfunction. According to Medline Plus, a service of the US National Library of Medicine, ischemic cardiomyopathy is the most common form of heart disease in the United States. The symptoms, like shortness of breath and cough, usually develop slowly over time, but sometimes a patient can present with an unexpected heart attack.

Ischemic cardiomyopathy can be treated and managed with lifestyle changes. Although there is no cure, medication and medical devices can help the disease prognosis. Acute ischemic hypoxia can also be caused by carbon monoxide or cyanide poisoning, drug overdose, or lack of adequate oxygen due to smoke inhalation. Drowning and strangulation deaths are also attributed to lethal cases of ischemic hypoxia. People who travel to high altitudes may exhibit signs of “altitude sickness” which can often times be caused, in part, by ischemic hypoxia because the blood supply becomes less oxygenated and moves less quickly through the circulatory system.