Wireless systems used by many hospitals to keep track of medical equipment can cause potentially deadly breakdowns in lifesaving devices, researchers warn. Some of the microchip-based "smart" systems are touted as improving patient safety, but a Dutch study of equipment suggests the systems could actually cause harm. The wireless systems send out radio waves that can interfere with equipment such as respirators, external pacemakers and kidney dialysis machines. A U.S. patient-safety expert said hospitals should respond immediately to the "disturbing" results and conduct safety tests.