Among the most seriously injured was a 17-year-old boy, who remained in critical condition at UPMC Presbyterian hospital early Thursday following surgery, a hospital spokeswoman said. A knife had passed through his liver, diaphragm and some major blood vessels, but missed his heart and aorta.



The knife missed the boy's heart and aorta by millimeters, said Dr. Louis Alarcon, director of trauma surgery at UPMC Presbyterian, where the boy was being treated. He was on breathing machines and sedated, Alarcon said at a news conference.