Pathophysiology
Clinical meaning
Aortic dissection occurs when a tear develops in the inner layer (intima) of the aorta, allowing blood to surge through the tear into the media (middle layer). This creates a false lumen that can propagate proximally or distally, compromising blood flow to branch vessels. Stanford Type A involves the ascending aorta (most lethal) and Type B involves the descending aorta distal to the left subclavian artery. The nurse must recognize the sudden onset of severe tearing chest or back pain, monitor vital signs closely, maintain a calm environment, and report all changes immediately.