Final answer:
When a TPN bag is empty, the nurse should hang a solution that is isotonic and contains dextrose. The most appropriate solution among the options provided would be 5% Dextrose in 0.9% NS.
Step-by-step explanation:
When a TPN bag is empty and a new bag has not been mixed and delivered to the nursing unit, the nurse should hang a solution that is isotonic and contains dextrose. Among the options provided, the most appropriate solution would be 5% Dextrose in 0.9% NS (Normal Saline). This solution has the same osmolarity as the patient's body fluids and provides a source of glucose for energy.