What is the typical PaO2 measured in the uterine artery?

The typical partial pressure of oxygen (PaO2) measured in the uterine artery is approximately 30 mmHg. This value is reflective of the physiological environment during pregnancy where oxygen is transported from the maternal circulation to the placenta and then to the fetus.

In normal circumstances, the PaO2 in the uterine artery is significantly lower than the levels found in systemic circulation (which can be around 80-100 mmHg) due to the fact that blood in the uterine artery is partially deoxygenated as it serves the placenta and the developing fetus. This lower PaO2 is important for ensuring proper gas exchange, as the fetoplacental unit has its own oxygen demands and mechanisms for utilizing the oxygen available.

Values like 60 mmHg, 100 mmHg, and 120 mmHg are typically associated with maternal arterial blood rather than the uterine artery itself. The 100 mmHg and higher values are characteristic of well-oxygenated adult arterial blood, which is not representative of the situation in the uterine artery where oxygen is partially depleted. Therefore, understanding the physiological context of the uterine artery is crucial for interpreting oxygen levels accurately.