Which measure indicates hypoxemia during mechanical ventilation?

Decreased oxygen saturation is a direct and reliable indicator of hypoxemia, which refers to low oxygen levels in the blood. During mechanical ventilation, maintaining adequate oxygenation is critical, and a drop in oxygen saturation can signify that the patient is not receiving sufficient oxygen, either due to poor ventilation-perfusion matching, insufficient tidal volume, or other respiratory complications.

In the context of mechanical ventilation, oxygen saturation is typically monitored using pulse oximetry. A reading below the normal range (usually under 90% or 92%, depending on clinical guidelines) suggests that the patient may be experiencing hypoxemia, requiring immediate assessment and potential intervention to improve oxygenation, such as adjusting the ventilator settings or increasing supplemental oxygen.

The other options, while potentially relevant to broader respiratory status, do not directly indicate hypoxemia. Increased respiratory rate can occur in response to many factors, including anxiety, pain, or metabolic demand, but does not confirm oxygenation status. Increased tidal volume may be employed to improve oxygenation, but does not itself reflect hypoxemia. Decreased arterial blood pressure could signal different complications such as hypovolemia or respiratory failure but is not a specific measure for hypoxemia. Therefore, decreased oxygen saturation is the clear indicator