Final answer:
The nurse should discontinue and discard the nearly empty IV bag as it has exceeded the usual 24-hour hang time, and replace it if necessary, ensuring patient safety and adherence to infection control protocols.
Step-by-step explanation:
The question pertains to the management of an intravenous (IV) solution that has not completed infusion by the expected time. The correct action for the nurse to take when identifying there is about 50mL left in the IV bag that was supposed to be infused by now is B. Discontinue the solution and discard. IV solutions typically have a maximum hang time recommended by hospital policy and manufacturers, usually between 24 to 48 hours after initiation, to reduce the risk of bacterial contamination. Since it has been over 24 hours (hung yesterday at 0700, now it's after 0730 the next day), the nurse should discard the current bag and, if necessary, hang a new bag as per the physician's order to maintain sterility and patient safety. Moreover, it is not appropriate to turn up the IV rate to infuse the rest rapidly without a doctor's order because it could cause fluid overload or other complications.