As if open-heart surgery isn’t enough to worry about, patients who have undergone the procedure in Springfi eld recently have received letters warning that they could be at risk of contracting an infection from a device used to heat and cool blood during operations. According to the federal Centers for Disease Control, the devices could have been contaminated while being manufactured, and while the risk is low (the CDC puts the odds at less than 1 percent), the infections ultimately can prove deadly, according to the CDC. The federal government isn’t requiring hospitals to notify patients, but both Memorial Medical Center and St. John’s Hospital have sent out letters. “To date, Memorial has not had any patients with this rare bacterial infection,” Memorial spokesman Michael Leathers wrote in an email. “There have been no reported cases in Illinois.” Dr. Marc Shelton, president of Prairie Cardiovascular at St. John’s, said that slightly more than 1,300 patients who have undergone surgery during the past 2 ½ years have received notice. “We talked about it and thought, well, we would notify patients,” Shelton said. “On the one hand, you don’t want to alarm people unnecessarily. On the other hand, it’s not unreasonable to tell people about it, either.” Shelton said that just one of seven devices used at St. John’s to heat and cool blood during surgery was the type identifi ed by the CDC as being a potential source of infection. “It’s no longer being used at St. John’s,” Shelton said. “It was a popular heatercooler. Fifty percent of the ones used in the U.S.