Questions have arisen before at the North Philadelphia hospital, where more than 80 percent of patients are eligible for Medicaid. In a whistle-blower lawsuit filed against St. Christopher's in September 2012, a former employee alleged that from April 2007 through April 2009, 10 of the hospital's heart-surgery patients died or suffered neurological complications due to deficient care. That case, filed by a specialist who operated the heart-lung bypass machine during operations, is pending, and the hospital has denied wrongdoing.