Final answer:
For a patient with polycythemia vera, the nurse should assist with or perform phlebotomy at the bedside to help reduce blood viscosity and hematocrit levels.
Step-by-step explanation:
The important action for the nurse to initiate for a patient with polycythemia vera would be B. Assist with or perform phlebotomy at the bedside. Polycythemia vera is a type of bone marrow disease that leads to excessive production of erythrocytes, increasing the viscosity of the blood. This can raise blood pressure and make it more difficult for the heart to pump blood. As part of the treatment, the nurse may assist with or perform phlebotomy to reduce the hematocrit and decrease the blood viscosity, thereby improving the patient's condition and symptoms.