At this stage in the rollout of Google Glass, it may seem the gadget's "cool factor" exceeds its practicality. For cardiologist Jordan Safirstein, however, it has already taken its rightful place in the operating room alongside his other surgical equipment. He's found his Glass has quickly become everything from a lectern to a blackboard to a telephone. "Okay, Glass: Make a video call," Safirstein said in a firm voice as he began a recent cardiac catheterization and stent insertion on a 41-year-old patient. Medicine has always been quick to find new uses for new technology, said Jeremy Greene, an internist who teaches medicine and the history of medicine at Johns Hopkins University.