Normal arterial partial pressure of oxygen (PaO₂)
May 29, 2022
Source: Cainiu Health
Dr. Li Man
Introduction
The normal arterial partial pressure of oxygen (PaO₂) is 80–100 mmHg. In fact, PaO₂ correlates with age. For individuals over 70 years old, a PaO₂ of 80 mmHg is not necessarily the lower limit of normal. Indeed, in some elderly patients, the lower limit of normal may be as low as 78–80 mmHg.
In daily life, there are numerous diseases—each with its own name—but many people are unfamiliar with certain disease-related terms, including associated numerical values. One such parameter is the partial pressure of arterial oxygen (PaO2). So, what is the normal range for PaO2?
Normal Value of Arterial Oxygen Partial Pressure (PaO2)
The normal PaO2 ranges from 81 to 100 mmHg. In practice, PaO2 generally correlates with age. For individuals over 70 years old, a PaO2 of 79 mmHg is not necessarily considered abnormal; rather, the “normal” range may shift downward with advancing age—for example, to 78–81 mmHg.
PaO2 is a key indicator used to assess whether hypoxia is present. It is measured via arterial blood gas (ABG) analysis. Patients with respiratory disorders or cardiac insufficiency are often required to undergo ABG testing. This test helps identify conditions such as hypoxemia or respiratory failure and can also detect carbon dioxide retention.
Clinically, a PaO2 between 61 and 81 mmHg is classified as hypoxemia; a value below 61 mmHg indicates respiratory failure. Once respiratory failure develops, many patients often have underlying chronic respiratory conditions, such as chronic obstructive pulmonary disease (COPD) or bronchiectasis. We hope this information has been helpful!
