How do hypoxemia and hypoxia differ?

Hypoxemia and hypoxia are terms often used interchangeably, but they refer to distinct concepts related to oxygen availability.

Hypoxemia specifically describes a condition characterized by low levels of oxygen in the arterial blood. This deficiency can be measured through arterial blood gases (ABGs), and it indicates that the lungs are not effectively oxygenating the blood due to various potential causes like respiratory disease, altitude, or ventilation-perfusion mismatches.

On the other hand, hypoxia refers to the inadequate oxygen supply to tissues or organs, regardless of blood oxygen levels. This condition can arise from hypoxemia but can also be caused by other factors such as anemia, carbon monoxide poisoning, or impaired cellular utilization of oxygen. While hypoxemia typically leads to hypoxia, it is important to recognize that tissues can be hypoxic even if blood oxygen levels are normal.

Understanding this distinction helps in determining appropriate interventions, as treating hypoxemia may resolve the hypoxia if the issue is primarily with oxygen delivery through the blood.