Overwhelmed with $576 million in debt, hospital operator LifeCare has filed for Chapter 11 bankruptcy protection, and plans to sell itself. The Plano, Texas, chain runs 27 long-term hospitals Texas, Pennsylvania, and eight other states. It said it will continue to do business and pay its employees through the bankruptcy process. The company, which was acquired by private equity firm Carlyle Group LP in 2005, said it has agreed to be bought by a group of its senior secured lenders, but hopes to see what results from an auction supervised by the bankruptcy court.