Decreased oxygen saturation

What is low oxygen saturation?

Oxygen saturation describes the percentage of hemoglobin that has bound oxygen. Hemoglobin is a protein complex that binds oxygen in the red blood cells. Colloquially, hemoglobin is also known as the pigment in red blood cells. It is loaded in the lungs and transports the oxygen to the organs. Oxygen saturation is also an important parameter for assessing respiratory function. A high level of oxygen saturation is important in order to supply all organs with valuable oxygen. It can be measured using a pulse oximeter, which is often attached to the finger. A value between 96% and 99% is normal. Below 96% one speaks of a decreased oxygen saturation, below 90% it requires treatment.

What are the causes of decreased oxygen saturation?

There are a number of reasons for decreased oxygen saturation. The most common

The causes are lung diseases. These include diseases such as:

  • COPD
  • bronchial asthma
  • Lung tumors
  • Pulmonary fibrosis
  • Lung infection.

However, diseases of other organs can also lead to decreased oxygen saturation, such as:

  • Heart failure
  • Circulatory disorders
  • Kidney diseases with disorders of the acid-base balance

Other causes can be carbon monoxide poisoning in fires. But it doesn't have to be a disease. Even with anesthesia, a short-term decrease in oxygen saturation can occur. It is used by the anesthetist to assess the anesthesia.

COPD as a cause

Chronic obstructive pulmonary disease (COPD) is a very common lung disease that mainly affects the elderly and smokers. With her there is a chronic narrowing of the airways. Due to the constriction, the lungs can no longer expand when inhaled and the oxygen exchange surface is lost. As a result, not every hemoglobin molecule can be loaded with oxygen. As the disease progresses, patients have increasingly low levels of oxygen saturation. This can initially be compensated by the body, but in the long term the patients also need oxygen from bottles.

Read more on our page about this disease: Symptoms of COPD

Pneumonia as the cause

In pneumonia, a bacterial infection causes inflammation of the lung tissue and the alveoli. In addition to symptoms such as fever, cough, and feeling sick, there is also a reduced oxygen saturation. Patients often have difficulty breathing due to the inflammation. In addition, there is often a build-up of slime that covers the oxygen exchange surface, so that here, too, hemoglobin can no longer be loaded with oxygen as well.

Read more on the subject at: lung infection

Narcosis as the cause

During anesthesia, there are often fluctuations in oxygen saturation. It is used by the anesthetist to assess the anesthesia. During anesthesia, the human lungs are artificially ventilated by a ventilator. There are various options for anesthesia and ventilation. If the ventilation is insufficient or there are problems, the anesthetist can see this from the low oxygen saturation. Then the anesthetist can increase the oxygen supply.As a rule, these short-term fluctuations have no effect on the patient.

Read more on the subject at: Anesthesia - procedure, risks and areas of application

Asthma as the cause

In bronchial asthma, chronic inflammation leads to a narrowing of the airways. Symptoms usually include shortness of breath and night coughing. Often there is an allergic genesis. Similar to asthma, there is a reduced oxygen exchange area due to the narrowing. In addition, there is often massive slime formation, which also reduces the surface area. As a result, the oxygen uptake is disturbed and the oxygen saturation is reduced.

Read more on the subject at: bronchial asthma

What are the symptoms of low oxygen saturation?

Decreased oxygen saturation is also known as oxygen deficiency or hypoxemia. An acute lack of oxygen can lead to symptoms such as weakness, malaise and dizziness. Mountaineers know this feeling when they are traveling at high altitudes, where the oxygen content in the air is lower. The body tries to compensate for the lack of oxygen by making the heart pump faster and breathing faster. This pumps the blood faster through the lungs with the aim of loading it with oxygen more quickly. If there is no improvement, shortness of breath, chest pain, tremors and sweating can occur. Long-term lack of oxygen eventually leads to loss of consciousness.
Another sign of insufficient oxygen saturation in the blood is cyanosis, a blue discoloration of the skin and mucous membranes. A distinction is made between peripheral and central cyanosis. In peripheral cyanosis, the fingers and toes of humans are primarily affected and there are bluish discolorations. With central cyanosis, there is also a bluish discoloration of the tongue.

How can you increase oxygen saturation?

If the oxygen content of the blood is low, the body instinctively tries to compensate for this. To do this, he tries to supply more blood with oxygen as quickly as possible. This happens through a faster and increased pumping power, which is associated with an increased heart rate and blood pressure, and an increased breathing rate. But this is harmful to the heart and lungs and in the long run the body cannot withstand the low oxygen content.

It is therefore important to start early with a lifestyle change or breathing training, especially in the case of chronic lung diseases, in order to counteract a reduced oxygen saturation prophylactically. The most important thing is to stop smoking. Smoking damages the lungs massively and stopping smoking, no matter how long you have been smoking, always has a positive effect on oxygen uptake. We also recommend normalizing your body weight and exercising regularly, especially endurance sports or outdoor sports. Mountain air and sea air in particular have a positive effect on breathing, so it is advisable to take a vacation or a cure there. In addition, special breathing training can help to improve the ventilation of the lungs and thus the oxygen uptake. Some physical therapists have special training in breathing training. Sports like yoga are also good for breathing.

If all these measures are still not enough, medication must be taken. Some medications, such as inhaled corticoids (e.g. cortisone) or salbutamol, widen the airways and thus improve the exchange of oxygen. In some cases, patients are dependent on the help of additional oxygen. This is done using special portable bottles and nasal cannula and can also be done at home.

When is a low oxygen saturation critical?

The normal value for oxygen saturation is between 96% and 99%. 100 percent is not possible for physiological reasons. Values ​​below 96% are referred to as reduced saturation. Patients often have mild breathing problems. For patients with chronic lung diseases such as COPD or asthma, values ​​below 96% can be normal and can be compensated by the body.

In general, it is said that an oxygen saturation of below 90% requires treatment and, in the long term, a value of below 85% is critical. With a long-term low oxygen content in the blood, the organs and cells of the body can no longer be adequately supplied with oxygen. However, oxygen is vital for all cells. The organs are no longer supplied with energy and in the long term the tissue perishes. This condition is also no longer reversible.

The heart and brain in particular are the organs that are affected first as they require a lot of energy and oxygen. The consequences are tissue damage that can lead to disability and ultimately death.

What are the consequences of decreased oxygen saturation?

Permanently low oxygen saturation can have serious consequences for the body. As a result of the compensation, the heart has to pump faster, which is harmful in the long term and in turn requires more oxygen. The consequences are heart failure (heart failure) and high blood pressure (arterial hypertension). In addition, the pulmonary vessels narrow due to the lack of oxygen through a physiological mechanism. This creates a higher pressure in the pulmonary vessels (pulmonary hypertension). As a result, the heart has to pump against a higher pressure, which in turn is harmful to the heart and can lead to heart failure and heart valve damage. Due to the increasing work of the heart, it also needs more oxygen. If it does not receive this, it can lead to heart attacks.

But not only the heart is damaged by the lack of oxygen. The brain is also dependent on oxygen. If there is insufficient oxygen, the first symptoms are concentration problems, memory problems and headaches. Chronic oxygen deficiency in the brain can damage the brain tissue (hypoxic-ischemic encephalopathy). This is accompanied by neurological failures. The consequences are severe disabilities, dementia and ultimately death.

Does decreased oxygen saturation have consequences for life expectancy?

A permanently reduced oxygen saturation has massive effects on life expectancy. Long-term lack of oxygen is life-threatening. In children and newborns, even a short-term lack of oxygen can lead to lifelong disabilities and limitations. A chronic lack of oxygen can also lead to severe restrictions in adults. The heart and brain are the first organs with sequelae. Because the body tries to compensate for the lack of oxygen, additional diseases occur that limit life expectancy. If the oxygen deficiency is not adequately treated, the patients have a severely limited life expectancy.