ABG Interpretation: PaO2 (Partial pressure of Oxygen)

This is a ABG interpretation series, we have discussed the PaO2 significance in this chapter.
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Arterial Blood gases or ABG is a standard measure of metabolic and respiratory functions in our body, as it gives clues about the gases in the blood such as carbon dioxide and Oxygen.
We have learned different components of ABG in the previous chapter, now we will see the significance of PaO2 in our blood and Diagnostic approach to ARDS.
Let's get started.
What happens when the partial pressure of oxygen drops below the normal level and what does it mean?
As we know, our blood carries oxygen to the cells and helps them keep alive and working.
The normal level of PaO2 in the blood is between 75 to 100 at room air.
Here we have to consider two factors.
The normal level of oxygen in blood and Room air.
If the Normal level of oxygen in the blood drops below 75 when the patient is on Room air or not taking any oxygen therapy, it's called Hypoxia.
Hypoxia is life-threatening if the PaO2 level is dropping below 50 as it corresponds to ARDS or acute respiratory distress syndrome.
ARDS is of two types
Hypoxemic respiratory failure
Hypercapnic respiratory failure.
If Hypoxia, it's hypoxemic respiratory failure.
If the level of PaCO2 in blood increases, it will be hypercapnic respiratory failure, which we will talk about in the next lesson.
So how Hypoxemic respiratory failure is classified?
What are the criteria for Grading ARDS?