Final answer:
For a patient with stage 2 chronic kidney disease undergoing a procedure with contrast media, the nurse should prioritize ensuring the patient is well hydrated before the procedure to help protect kidney function.
Step-by-step explanation:
The priority action a nurse should perform for a 52-year-old man with stage 2 chronic kidney disease (CKD) who is scheduled for an outpatient diagnostic procedure using contrast media is to ensure the patient is well hydrated before the procedure. Adequate hydration is crucial because contrast media can potentially harm the kidneys, particularly in patients with pre-existing kidney conditions. By ensuring proper hydration, the kidneys can more effectively dilute and excrete the contrast media, minimizing the risk of further kidney damage.