An elderly male presented for emergent repair of a ruptured abdominal aortic aneurysm. For anticipated volume resuscitation, vasopressor administration, and hemodynamic monitoring, a large-bore central venous catheter was placed in the left internal jugular vein under ultrasound guidance before surgical incision. Initially, there were no readily apparent signs of venous perforation. However, a massive left hemothorax developed because of perforation of the brachiocephalic vein and violation of the pleural space. This case report discusses both prevention and management of such a complication.