Final answer:
The nurse should re-evaluate the IV therapy prescription if the client's BUN levels indicate renal dysfunction.
Step-by-step explanation:
The nurse should re-evaluate the IV therapy prescription if the client's BUN (blood urea nitrogen) levels indicate renal dysfunction. BUN is an indicator of kidney function, and elevated levels can suggest that the kidneys are not effectively filtering waste from the blood. This can be a sign that the IV fluid therapy may need to be adjusted or discontinued.