What is hypoxic respiratory failure evidenced by?

Hypoxic respiratory failure is characterized primarily by low levels of arterial oxygen, which is indicated by decreased PaO2 levels. PaO2 is a measure of the partial pressure of oxygen in arterial blood and reflects how effectively oxygen is being transported. When this level drops significantly, it indicates that the body is not receiving enough oxygen, leading to inadequate oxygenation of tissues and potential organ dysfunction.

In contrast, while an inability to ventilate or remove carbon dioxide can play a role in various forms of respiratory failure (primarily hypercapnic respiratory failure), they do not specifically represent hypoxic respiratory failure. Moreover, correct oxygen perfusion implies that oxygen is adequately delivering to tissues, which is not the scenario in hypoxic respiratory failure. Therefore, the hallmark of hypoxic respiratory failure is clearly low PaO2 levels.