Final answer:
The nurse should intervene when the LPN and CNA do not secure the bed wheels before moving a patient, as it's essential for patient and staff safety.
Step-by-step explanation:
The subject of this question relates to the correct procedures that healthcare professionals, such as Registered Nurses (RNs), Licensed Practical Nurses (LPNs), and Certified Nursing Assistants (CNAs), must follow when moving a patient up in bed to ensure the patient's safety. The nurse should intervene in the situation where the LPN and CNA do not secure the bed wheels before the procedure. This is a critical safety step to prevent the bed from moving unexpectedly, which could potentially harm the patient or the healthcare workers. The use of a friction-reducing sheet by LPN and proper body mechanics by CNA, as well as effective communication between LPN and CNA, are all correct and safe practices that should be encouraged.