Arterial Hypoxemia: What It Is and What Causes It

Arterial hypoxemia relates to the insufficient presence of oxygen in the human body. It's a serious situation that can either be acute or chronic. This article explains the possible causes of the disorder and its effects.
Arterial Hypoxemia: What It Is and What Causes It

Last update: 11 February, 2021

Arterial hypoxemia occurs when there’s a lower amount of oxygen transported by the arteries than normal. It’s a serious situation because one of the primary functions of the arteries, is, indeed, carrying oxygen to the cells in the body.

Cells can’t function without an adequate amount of oxygen. Furthermore, severe arterial hypoxemia endangers the vital functions of the body. In fact, cells die if the situation occurs over time.

How is arterial hypoxemia diagnosed?

There are two medical procedures to determine arterial hypoxemia.

  • Millimeters of mercury: Under normal conditions, the amount of oxygen in the arteries should range from 75 to 100 millimeters of mercury. However, if the measurement falls below 60 millimeters of mercury, the patient needs external oxygen.
  • Oxygen saturation: This is the most accessible method of measurement. It measures the percentage of oxygen saturation of the blood. The patient has a small device like a saturometer connected to one finger. This measures the percentage of oxygen saturation of their blood. Normal oxygen saturation levels are between 96 and 100 percent. Below 95 percent gives cause for alarm. However, if it’s below 90 percent the patient needs supplemental oxygen.

There are three stages involved in the process of oxygen reaching the cells. These are in three different areas. If there’s a defect in any one of these three stages, it can disrupt the complete process of cellular functioning. These stages are:

  • Oxygen from the environment: The person’s location must have an adequate concentration of oxygen. Lack of oxygen occurs at the top of a mountain, for example, or in a room that’s contaminated with carbon monoxide.
  • Healthy lungs: The respiratory system must be able to take oxygen in from the environment. It then passes the oxygen onto the arteries. However, this process becomes altered in illnesses such as asthma.
  • Arterial blood: This is where arterial hypoxemia is actually determined. It’s the stage where the oxygen that’s been taken in from the environment by the lungs is transported throughout the body. Indeed, blood carries oxygen to every cell in the human body.

Causes of arterial hypoxemia

The most common causes of arterial hypoxemia are:

  • Chronic obstructive pulmonary disease (COPD): These diseases include asthma, emphysema, and chronic bronchitis. They all affect the lungs. In fact, they interrupt the entry of oxygen. This compromises the third stage mentioned above, where the blood distributes oxygen throughout the body.
  • Heart problems: Some heart conditions affect communication between the lungs and the arteries. Oxygen has to pass from the respiratory system to the circulatory system via the lung-heart connection. However, if this connection is affected at all by any medical condition, it decreases the oxygen available for the arteries.
  • Pneumonia: Patients with infectious pneumonia often develop arterial hypoxemia. In severe cases, their oxygen saturation levels are monitored daily. This is in order to assess their condition.
  • Anemia: Red blood cells in the arteries transport oxygen through the body. Therefore when there are fewer blood cells this affects the transport of oxygen. This happens with anemia. Anemia varies in its severity. In fact, the extent of its severity also affects the severity of the arterial hypoxemia suffered by the patient.
  • Medication: Drugs derived from opioids and morphine can cause the effects of arterial hypoxemia. Indeed, patients should only ever use these medications in the suggested doses. Furthermore, they should only use them with a prescription and under professional supervision.
An xray of the lungs.
The lungs play a critical role in transporting oxygen from the environment to the arteries.

Symptoms of arterial hypoxemia

A lack of oxygen in the cells of the body causes a range of symptoms. Some symptoms correspond to the organ most affected by arterial hypoxemia. However, there are also more general symptoms.

Common symptoms include:

  • Changes in skin color: Arterial hypoxemia can cause paleness. This is especially relevant in anemia. In addition, it can cause cyanosis. This is a bluish coloration of the skin. In fact, it’s an obvious sign of a lack of oxygen.
  • Fainting: If the brain doesn’t receive enough oxygen, then it reduces its functions. This causes fainting.
  • Headache: If arterial hypoxemia is intermediate and persistent the patient might suffer headaches. Furthermore, there might be signs of swelling. In addition, the patient receives no relief when taking the usual anti-inflammatory drugs.
  • Motor coordination problems: The brain needs oxygen to carry out its functions. Among these functions is motor coordination. This is necessary for functions like walking and moving. In arterial hypoxemia, the sufferer might experience difficulty in the simplest of activities. This could be walking or trying to catch something with their hands, for example.
  • Vomiting and nausea.
  • Arrhythmias.
  • Muscle cramps. These are mainly nocturnal.
Fingers with symptoms of cyanosis.
Cyanosis is a bluish coloration of the skin, which can be a sign of arterial hypoxemia.

Long term effects

If arterial hypoxemia persists over a long time, the body tries to adapt to the situation. One way in which it does this is to produce more red blood cells to transport oxygen. This process is called polyglobulia. This situation can occur in the body without causing any changes. However, medical professionals must monitor it regularly. This is to check that the condition doesn’t become excessive. If not, it could cause abnormal circulation of the blood.

Arrhythmias are another long-term effect of arterial hypoxemia. When arrhythmias occur, then the heart changes its frequency and interval between beats. This is to compensate for the lack of oxygen. However, if the arrhythmia gets out of control, the patient’s life could be at risk.

Finally, arterial hypoxemia affects the brain. Indeed, patients with COPD often suffer neurological disturbances such as depression, memory loss, and attention loss. These symptoms are all linked to arterial hypoxemia.

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  • Puerta Vilchez, M., and P. Azcón González de Aguilar. “Hipoxemia y oxigenoterapia no invasiva.” Revista Española de Pediatría 57.5 (2001): 383-391.
  • Bonay, M. “Conducta diagnóstica y terapéutica ante una hipoxemia.” EMC-Tratado de Medicina 9.1 (2005): 1-8.