What lab finding would confirm hypoxemic respiratory failure?

The lab finding that would confirm hypoxemic respiratory failure is a PaO2 less than 60 mmHg. In the context of respiratory failure, particularly hypoxemic respiratory failure, the primary issue is inadequate oxygenation of the blood. The PaO2 measurement directly reflects the amount of oxygen dissolved in the arterial blood. A value below 60 mmHg indicates significant impairment in oxygen transfer, which is characteristic of hypoxemic respiratory failure.

In contrast, elevated levels of PaCO2, as indicated in another option, suggest hypercapnia, which is more related to ventilatory failure rather than exclusively to hypoxemia. Normal bicarbonate levels could indicate a normal metabolic response to respiratory challenges, but they do not provide definitive evidence of oxygenation status. Similarly, decreased hemoglobin concentration may suggest anemia, which can lead to inadequate oxygen delivery but does not directly indicate hypoxemic respiratory failure on its own. Therefore, a PaO2 less than 60 mmHg is a clear indicator of hypoxemic respiratory failure.