The mouse slips, and the emergency room doctor clicks on the wrong number, ordering a medication dosage that's far too large. Elsewhere, in another ER's electronic health record, a patient's name isn't clearly displayed, so the nurse misses it and enters symptoms in the wrong person's file." There are new categories of patient safety errors" in emergency rooms that didn't exist before the push to use electronic record systems, said Raj Ratwani, who researches health care safety and is the scientific director for MedStar Health's National Center for Human Factors in Healthcare in Washington, D.C.