Every year, an estimated 4,000 cases of "retained surgical items," as they are known in the medical world, are reported in the United States. The vast majority are gauzelike sponges used to soak up blood. During a long operation, doctors may stuff dozens of them inside a patient to control bleeding. In recent years, new technology and sponge-counting methods have made it easier to remedy the problem. But many hospitals have resisted, despite the fact that groups like the Association of Operating Room Nurses and the American College of Surgeons have called on hospitals to update their practices. As a result, patients are left at risk, said Dr. Verna C. Gibbs, a professor of surgery at the University of California, San Francisco.