A special form of hypoxemia – so-called silent hypoxemia or happy hypoxemia – has recently occurred more frequently with COVID-19 infections. In this, patients exhibit neither shortness of breath nor accelerated breathing, despite severe hypoxemia with oxygen saturation values down to below 70%. Although the typical symptoms of such low oxygen saturation levels are absent, decompensation of the lungs progresses rapidly with such severe hypoxemia, and is life-threatening.
Causes of hypoxemia
Causes of low blood oxygen saturation include:
- Impaired breathing, such as due to head injuries, sleep apnea/snoring, or stroke
- Pulmonary diseases such as pulmonary embolism, pneumonia, asthma, or chronic obstructive pulmonary disease (COPD)
- Blood disorders such as anemia or blood formation disorders
- Cardiovascular diseases such as heart failure or myocardial infarction
- Certain environmental factors such as extreme altitude
- Poisoning, such as from medications, drugs, or carbon monoxide
What to do when blood oxygen saturation is low
If the oxygen saturation in the blood is too low, additional oxygen can be supplied to the lungs by oxygen therapy.
Pulse oximetry or blood gas analysis is used to determine oxygen saturation, and the amount of supplemental oxygen required. The required oxygen is then supplied to the lungs, usually via a nasal cannula.
Oxygen therapy can be used in acute therapy as well as for chronic care.
As part of chronic care therapy, 3 types of system are usually used: Oxygen concentrators, compressed gas systems, and liquid oxygen systems. Compressed gas and liquid oxygen systems require a tank of oxygen in a liquid or gaseous compressed state, respectively. Oxygen concentrators do not require an oxygen tank. They merely separate oxygen from nitrogen, thereby increasing the oxygen content in the inhaled air.