Final answer:
Option c is the correct answer. The priority assessment for an older patient with nausea and vomiting is blood pressure and pulse to determine circulatory stability and potential shock. While respiratory status, urine output, and skin integrity are also important, they follow blood pressure and pulse in acute priority.
Step-by-step explanation:
An older patient admitted with nausea and vomiting requires a priority assessment which, among the options provided, would be c. Blood pressure and pulse. This assessment is vital for determining the patient's hemodynamic status and the risk of shock or dehydration, which can be a direct consequence of excessive vomiting. A significant drop in blood pressure, as indicated by the reference to a patient with a blood pressure of 70/45 and signs of confusion and thirst, suggests a state of hypoperfusion that can lead to shock.
Assessment of respiratory status is also important, especially when there is a risk or presence of aspiration due to vomiting. Urine output and skin integrity are important as well, but they do not take precedence over circulatory and respiratory assessments in immediate acute situations.
The role of the kidneys in regulating blood pressure is highlighted by their contribution to the renin-angiotensin-aldosterone system and their ability to retain or lose water and sodium. If the kidneys fail, as when blood pressure is severely low, their inability to function can have severe consequences, such as metabolic acidosis, rising potassium levels, and heart arrhythmias, ultimately affecting homeostasis.