Final answer:
The nurse should prioritize assessing vital signs for a patient saturating perineal pads with blood post-hysterectomy, due to the risk of hemorrhage and the need for potential medical intervention. The correct option is B) Assess vital signs and hemoglobin levels.
Step-by-step explanation:
The nurse's priority action for a patient who had a vaginal hysterectomy the previous day and is now saturating perineal pads with blood should be to assess vital signs and hemoglobin levels. This is critical in detecting any signs of hemorrhage and initiating appropriate medical intervention. The initial physiological response to hemorrhage includes mechanisms aimed at increasing blood pressure and maintaining blood flow. If the blood loss cannot be controlled naturally, medical intervention will be required to restore blood volume and prevent complications such as shock, which could lead to organ failure as seen in Barbara's case, who experienced sepsis and subsequent multi-organ failure.