Final answer:
The RN should intervene when an LPN is assigned a patient receiving (b) racemic epinephrine for croup due to the potential for serious side effects that require the advanced skills of an RN.
Step-by-step explanation:
The question at hand involves understanding which patient assignments might require intervention by a Registered Nurse (RN) when they are initially given to a Licensed Practical Nurse (LPN). In this case, the RN would need to intervene if an LPN is assigned a patient receiving racemic epinephrine for croup. This medication can be associated with serious side effects like significant cardiovascular effects, requiring closer monitoring and assessment skills that are within the RN's scope of practice.
Therefore, an LPN may not be allowed or may not have the experience to manage the potential complications that may arise with racemic epinephrine administration. The other medications listed, including methylprednisolone for lumbar radiculopathy, ketorolac for pleurisy, and tamsulosin for BPH, typically do not require such a high level of monitoring and can often be managed by an LPN, assuming they are within their scope of practice and competency.