Identification

Normal blood oxygen levels are between 95 percent to 100 percent at sea level, according to the Mayo Clinic. When this value drops below 90 percent, borderline or mild hypoxemia begins, with severe cases showing readings below 80 percent.

Internal Causes

In some cases, hypoxemia is due to problems with proper functioning of the lungs due to illness or disease, such as airway obstruction, acute respiratory distress syndrome, chronic obstructive pulmonary disease, emphysema, interstitial lung disease, pneumonia, blood clots within the lungs, sleep apnea, scarring of the lungs and swelling of the lungs. Additional possible causes of hypoxemia include anemia or lack of oxygen-carrying red blood cells, decreased pumping of the heart, shock and narcotic medications.

External Causes

Some causes of hypoxemia have nothing to do with the overall health of the patient and are based on external factors. Examples include difficulty breathing due to high altitude or drops in pressure, carbon monoxide poisoning and smoke inhalation.

Symptoms

Symptoms of hypoxemia include shortness of breath, fatigue, confusion and an inability to exercise or move.

Diagnosis and Treatment

Hypoxemia is usually diagnosed through a simple blood test or the use of an oximeter, which clips to the end of a finger and measures the amount of oxygen in your body. When your doctor discovers the hypoxemia, she quickly will administer oxygen to you through a mask.

Source

Mayo Clinic: Hypoxemia

The Hazards of Hypoxemia