Final answer:
The patient in the emergency department with a blood pressure of 70/45 and confusion is the highest priority.
Step-by-step explanation:
The highest priority client would be the patient in the emergency department with a blood pressure of 70/45 and confused state. This indicates that the patient is experiencing hypotension, which can be a sign of a life-threatening condition such as shock. The patient's complaint of thirst may also be indicative of dehydration. The nurse should prioritize this client and provide immediate care to stabilize their condition.