Final answer:
The priority action for a client with a ruptured aortic aneurysm is to immediately prepare the client for surgery, due to the life-threatening nature of this condition.
Step-by-step explanation:
The priority action for a client who presents with a ruptured aortic aneurysm is to prepare the client for surgery. Aortic aneurysm rupture is a life-threatening condition requiring immediate surgical repair to prevent fatal consequences. While antihypertensive medication and β-blockers can be part of the preoperative management, the immediacy of surgery supersedes these interventions. An aortogram may have been part of the diagnosis process, but it is not a priority in the setting of a rupture where time is of the essence.