Final answer:
The most immediate action required is to address the disconnected central intravenous line for a patient taking epoprostenol (Flolan), as this can lead to a life-threatening situation.
Step-by-step explanation:
The assessment information that requires the most immediate action for a patient with primary pulmonary hypertension who is receiving epoprostenol (Flolan) is c. The patient's central intravenous line is disconnected. Epoprostenol is a potent vasodilator and antiplatelet agent that must be administered continuously through a central intravenous line. If the line is disconnected, the patient could suffer a rapid rebound in blood pressure, which could lead to a life-threatening situation. Immediate intervention is necessary to reconnect the line and ensure a continuous flow of medication.
Additionally, it's important to monitor blood pressure and oxygen saturation levels regularly for patients with pulmonary hypertension. Although the blood pressure of 98/56 mm Hg and oxygen saturation of 94% might warrant attention, they are not as immediately critical as the disconnected central line. A prolonged international normalized ratio (INR) indicates a risk of bleeding, but it also does not require as immediate an action as a disconnected central intravenous line.