What does the term "partial pressure of oxygen" refer to in diving with EANx?

The term "partial pressure of oxygen" specifically refers to the portion of the total pressure in a gas mixture that is due to the presence of oxygen. In the context of diving with Enriched Air Nitrox (EANx), this concept is crucial for understanding how the body absorbs and utilizes oxygen under pressure.

When divers are exposed to different depths, the total pressure increases due to the weight of the water above them. Each gas in the mixture, including oxygen, exerts pressure in proportion to its concentration. The partial pressure of oxygen is thus calculated by multiplying the fraction of oxygen in the mixture by the total pressure at the given depth. This value is important for assessing the risk of oxygen toxicity, as increased partial pressures beyond certain limits can lead to adverse effects on the body.

Recognizing the role of partial pressure allows divers to plan their dives safely, ensuring that they remain within safe operating limits when using EANx. This understanding helps in avoiding both hypoxia (insufficient oxygen) at shallower depths and hyperoxia (excess oxygen) at deeper depths, promoting safe diving practices.