Which intervention should be performed to improve a patient's oxygen saturation reading?

Placing the patient on oxygen is a direct and effective intervention for improving oxygen saturation readings. When patients present with low oxygen saturation, it often indicates that they are not getting enough oxygen in their bloodstream. Supplemental oxygen can help increase the amount of oxygen they receive, thus improving their saturation levels. It is a standard and critical intervention in cases of respiratory distress, hypoxia, or other conditions that impair gas exchange in the lungs.

The other options might have their own benefits in specific scenarios. For example, inserting an oropharyngeal or nasopharyngeal airway may help maintain an open airway, which can be essential in patients who are unable to breathe effectively on their own. However, these measures primarily focus on airway management rather than directly addressing oxygen saturation levels. Positioning the patient supine with legs elevated may be appropriate in certain situations, such as for shock, but it doesn't directly enhance oxygenation in the same way that providing supplemental oxygen does. Thus, for the specific goal of improving oxygen saturation readings, administering supplemental oxygen is the most appropriate choice.