Final answer:
The nurse should immediately contact the primary health care provider.
Step-by-step explanation:
Based on the findings of a drop in blood pressure and an increased pulse rate after a radical neck dissection, the nurse should immediately contact the primary health care provider. These changes could indicate hypovolemia, which is a decrease in blood volume. The provider may need to evaluate the client's condition and make necessary interventions, such as fluid replacement, to stabilize the blood pressure and pulse rate.