Final answer:
When a TPN bag is empty and a new one is not available, the nurse should infuse Dextrose 10% in water (D10W) as an interim solution to maintain blood glucose levels and prevent hypoglycemia.
Step-by-step explanation:
A nurse who finds that the current bag of TPN (Total Parenteral Nutrition) is empty and a new bag is not immediately available should opt for an alternative intravenous (IV) solution that closely mimics the osmolarity of TPN to prevent osmotic shifts and complications. Ideally, a dextrose 10% in water (D10W) should be infused until the new TPN bag is available. This solution provides a concentrated source of glucose to maintain the patient's blood glucose levels and prevent hypoglycemia, which can occur if TPN is suddenly stopped.
Other solutions like 0.45% sodium chloride, dextrose 5% in lactated Ringer's, or 0.9% sodium chloride are not as ideal. A 0.45% sodium chloride is a hypotonic solution and may not provide adequate glucose, dextrose 5% in lactated Ringer's includes electrolytes that may not be necessary, and 0.9% sodium chloride (normal saline) is isotonic but does not provide the necessary glucose support. TPN solutions are high in glucose content, which necessitates a higher glucose content in the interim solution such as D10W.