A Brief Summary of Hypoxia

A Brief Summary of Hypoxia

Hypoxia or oxygen starvation can be defined as deficiency of oxygen in the tissues of the body. It is different from hypoxemia which is caused by poor amount of oxygen present in the blood. Sometimes, hypoxemia can also lead to hypoxia, for instance, if tissues receive insufficient oxygen, it can be a result of inadequate levels of oxygen in the blood. However, there can be other causes too that result in hypoxia.

Signs & Symptoms

Generalized hypoxia may affect the whole body while tissue hypoxia disturbs a specific organ or part of the body. The symptoms of hypoxia vary from person to person. Also, this variation depends on how long the condition has been present in the tissues. These include:

  • Dyspnea – shortness of breath

  • Syncope – fainting or dizziness

  • Fatigue, confusion, lack of judgment

  • Tachypnea – elevated respiratory rate

  • Tingling or warm sensation

  • Hypertension – elevated blood pressure

  • Lack of coordination

  • Headache

  • Tunnel vision or other visual changes

  • Polycythemia – elevated red blood count

  • Cyanosis – slightly blue tinge to the lips and the edges


Hypoxia can be categorized into various types or reasons including the following:

Metabolic hypoxia

This condition occurs when the tissues need more amount of oxygen than usual. While the tissues may properly absorb, carry, and use oxygen, it remains inadequate because of the condition constantly raising metabolism. Sepsis (an overwhelming infection) is an example of metabolic hypoxia.

Anemic hypoxia

Anemia is a condition where low levels of hemoglobin (red cells in the blood) result in a poor ability of blood to transport oxygen throughout the body. It eventually results in a reduced supply of this chemical to the tissues, and is known as anemic hypoxia.

Hypoxic hypoxia

In this condition, the tissues don’t get enough oxygen because of the low amount of oxygen in the blood that travels to the tissues. In some cases, hypoxic hypoxia can also be a result of inadequate breathing and other causes.

Stagnant or circulatory hypoxia

In this type of hypoxia, inadequate blood flow in the body results in poor oxygen in the tissues.


Watershed areas, the rental medulla/cortex and subendocardial tissue are some of tissues that are most vulnerable to lack of oxygen. However, vulnerability to hypoxia tends to vary between tissues. For instance, the brain is very vulnerable to lack of oxygen. If it doesn’t get this chemical element to complete aerobic metabolism, death can happen within a few minutes. Depending on the person’s training, the skeletal muscle in a leg or arm can go through anaerobic metabolism for some minutes or longer without needing oxygen.

Diagnosing Tests

There are a number of different diagnosing tests that can be used to determine the causes of hypoxia. These include arterial blood gases, oximetry, blood tests, EKG, X-ray or CT scan of the chest, bronchoscopy, echocardiogram, and MRI or CT scan of the head.


Depending on the duration, this condition can also be classified as chronic or acute. Chronic hypoxia means the condition has been persistent for some time while acute refers to a rapid onset of low oxygen. Because of the increased tissue vulnerability to lack of oxygen, hypoxia can cause damage to vital organs of the body including brain, heart and kidney. In brief, heart attacks lead to irreversible heart damage, brain damage follows in stroke, and kidney failure results in forming infarcts in the rental arteries that are responsible to supply blood to the kidney.


The treatment of hypoxia depends on the underlying cause. While your doctor is working to find out the cause, they may recommend oxygen therapy as the first step to take. Mechanical ventilation through a ventilator may be required in case of severe symptoms of hypoxia.

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