Final answer:
For a 72-year-old woman admitted with multiple myeloma, it is crucial to monitor fluid intake and output due to the risks of kidney complications and hypercalcemia associated with the disease.
Step-by-step explanation:
The nurse should include the action to monitor fluid intake and output in the plan of care for a 72-year-old woman admitted with multiple myeloma. This is important because multiple myeloma can cause kidney complications such as «cast nephropathy» which refers to kidney damage due to the excessive levels of light chains typically produced in this disease. These can form casts in the kidney tubules, leading to renal failure. Also, multiple myeloma can lead to hypercalcemia, which is an abnormally high level of calcium in the blood, caused by calcium release from affected bones and impaired kidney function to excrete the excess calcium. Monitoring fluid intake and output helps manage the potential risk of kidney damage and maintain kidney function. Furthermore, myeloma patients are particularly at risk for dehydration, which can exacerbate kidney problems and hypercalcemia.