Massachusetts hospitals are reporting more errors during surgery and invasive procedures, even after an intensive, decade-long campaign to reduce these mistakes—called "never events" because they're preventable and, with reasonable precautions, simply shouldn't happen. Errors disclosed to state health officials since 2011 included anesthesia injected into the wrong leg, a guidewire left inside a patient's vein, and a catheter threaded into a patient who didn't need one, according to hospital safety leaders. Several of them said the reported number of such incidents is rising as more care shifts to outpatient clinics, procedure rooms, and physicians’ offices, where administrators and caregivers generally have been less vigilant about implementing safety protocols of the sort required in most hospital operating rooms.