Final answer:
The nurse should prioritize the adult who had a cerebral arteriogram and now has a cool, pale right leg, as this suggests an urgent vascular issue that could lead to tissue damage if not addressed promptly.
Step-by-step explanation:
The rapid assessment of neurological function is crucial in an emergency to determine the extent of potential damage to the nervous system and to prioritize treatment. The scenario presents four patients, each with varying degrees of urgency. A Glasgow Coma Scale score of 13 indicates mild brain injury, and although it's serious, it's not as time-sensitive as an arterial occlusion.
A headache after lumbar puncture is usually a post-procedure side effect and is less urgent. Expressive aphasia, while concerning, typically does not require immediate intervention to prevent further damage, unlike the potential loss of limb due to arterial issues. The cool, pale leg is the most alarming sign, potentially indicating an acute arterial blockage, hence necessitating immediate action. Signs of stroke or a transient ischemic attack (TIA) require rapid assessment to minimize brain damage, but the cool, pale leg presents the situation with the highest risk of acute and severe harm.