For a 70-year-old woman with severe respiratory distress and a history of congestive heart failure, what immediate action should be taken?

The most appropriate immediate action in this scenario is to elevate the upper body and administer oxygen. In cases of severe respiratory distress, especially for a patient with a history of congestive heart failure, sitting the patient up can help alleviate the symptoms by decreasing pressure on the diaphragm and allowing for easier breathing.

Additionally, providing oxygen is crucial as it addresses the underlying issue of hypoxia, which is common in individuals experiencing respiratory distress. Supplemental oxygen can help improve the patient's oxygen saturation levels, enhancing overall respiratory function and comfort.

Elevating the upper body in this context also promotes better venous return and can help reduce pulmonary congestion, which is often exacerbated in patients with heart failure. Therefore, this action is both supportive and therapeutic, addressing the immediate needs of the patient in respiratory distress.