Final answer:
Marie's nurse should prioritize administering the blood transfusion while ensuring the infant's nutritional needs are met, potentially by having someone else feed the baby if Marie's condition does not allow for a safe interruption.
Step-by-step explanation:
In the scenario presented, the best thing for Marie's nurse to do is to assess both Marie's and her infant's immediate needs and coordinate care accordingly. Given that Marie is about to receive a transfusion, the administration of blood is a time-sensitive intervention that cannot be delayed, as it might be essential to her health. The infant, on the other hand, has been sleeping soundly, and while it has been 4 hours since the last nursing, the baby's current restful state indicates there may be flexibility.
Marie's nurse should consider the infant's feeding schedule and Marie's condition and recovery. If Marie is stable and the transfusion can be safely monitored by another member of the healthcare team, the nurse could potentially assist Marie in feeding her child. If not, the nurse might arrange for someone else, such as the infant's father or a nursery nurse, to feed the baby either via bottle with expressed breast milk or formula, ensuring the baby's nutritional needs are met without compromising Marie's care.
The priority here is to maintain the well-being and safety of both mother and child.