Arterial hypoxemia: what is it?

There is talk of arterial hypoxemia when the amount of oxygen that the arteries carry is less than normal. It is a serious picture because one of the primary functions of the arteries is precisely the transport of oxygen to the cells.

Without an adequate amount of oxygen, the cells cannot function. In the cases of severe arterial hypoxemia, the vital functions of the organism are at risk, with the possibility of cell death if prolonged over time.

To determine arterial hypoxemia Two measures are used in medicine:

• Milimeters of mercury: Under normal conditions, the amount of oxygen in the arteries should range between 75 and 100 millimeters of mercury. When the measurement is below 60 millimeters of mercury, external oxygen is required for the patient.
• Oxygen saturation: The most accessible measure is saturation through percentages. Small devices such as the saturometer connect to a finger to measure this percentage. An oxygen saturation between 96 and 100% is normal. Below 95% is an alarm sign and below 90% supplemental oxygen is required.

For oxygen to reach the cells, three steps must be completed in three different environments. If one of these three steps fails, then the final result, which is cellular functioning, is altered. These steps are:

• Oxygen from the environment: The place where the human being is must have an adequate concentration of oxygen. It may be missing when climbing a mountain, for example, or in rooms where it is contaminated with carbon monoxide.
• Healthy lungs: The respiratory system must be able to take oxygen from the environment to pass it to the arteries. Diseases such as asthma can alter this process.
• Arterial blood: This is where arterial hypoxemia is measured. It is the stage of oxygen transport that was taken from the environment through the lungs. The blood will carry that oxygen to every cell of the human body.

Causes of arterial hypoxemia

The most frequent causes of arterial hypoxemia are:

• Chronic obstructive pulmonary diseases (COPD): Among these pathologies we have asthma, emphysema and chronic bronchitis. By affecting the lungs, the entry of oxygen is interrupted and the third step, which is the distribution of oxygen through the blood, begins at a disadvantage.
• Heart problems: Some heart disorders affect communication between the lungs and arteries. Since oxygen must pass from the respiratory system to the circulatory system through the lung-heart connection, if there is any condition in this connection, the oxygen available to the arteries will decrease.
• Pneumonia: Patients with infectious pneumonia usually suffer from arterial hypoxemia. In severe cases that are hospitalized, oxygen saturation is monitored daily to determine the patient's condition.
• Anemia: The oxygen is transported in the arteries inside the red blood cells. When there are fewer red blood cells, oxygen transport is logically affected. That happens in anemias, whatever their origin. There are different degrees of anemia and that determines different degrees of severity of arterial hypoxemia.
• Medicines: The use of drugs derived from opioids and morphines has the adverse effect of arterial hypoxemia. These are medications that should be used at the indicated doses and always with a prescription and professional supervision.

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Symptoms of arterial hypoxemia

The lack of oxygen in the cells generates a range of symptoms. Some signs respond to the organ most affected by arterial hypoxemia and others are general signs.

Between the usual symptoms, we have:

• Changes in skin color: Arterial hypoxemia can lead to paleness, especially associated with anemia. On the other hand, it can generate cyanosis, which is the bluish coloration of the skin, an obvious sign of a lack of serious oxygen.
• Fainting: If the oxygen received by the brain is not enough, it will tend to reduce its functioning to the point of causing fainting or syncope.
• Headache: When arterial hypoxemia is intermediate and persistent, there is headache and signs of bulging. This pain is not relieved with common anti-inflammatories.
• Motor coordination problems: The brain needs oxygen to carry out all its regulatory functions. Among these functions is the motor coordination for walking and moving. In arterial hypoxemia there may be difficulties in simple activities such as walking or wanting to take something with your hands.
• Vomiting and nausea
• Arrhythmias
• Muscle cramps, Mainly nocturnal

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Long-term effects

If arterial hypoxemia persists over time, the human body will try to adapt to that new situation. One way to adapt is to produce more red blood cells for oxygen transport. The situation is called polyglobulia.

Polyglobulia can coexist in the body without causing alterations. Anyway, it must be checked regularly so that it is not excessive and alter the normal circulation of blood.

Arrhythmias are another long-term effect of arterial hypoxemia.. The heart changes its frequency and heartbeat interval to compensate for the lack of oxygen. If the arrhythmia gets out of control, life is at risk.

Finally, there is the brain effect. Among patients with COPD it has been shown that neurological disorders are very common, such as depression, memory losses and lack of attention. These alterations are linked to arterial hypoxemia.