Security audit of district hospitals, night patrolling, regulated access at large health facilities were among the measures the Centre on Wednesday asked states to implement to prevent violence against doctors. The directions came days after the Supreme Court, while hearing the rape-murder case of a junior doctor in Kolkata, ordered the Union health secretary to ensure states have basic measures in place to assuage doctors' concern over safety at workplaces till the court-appointed National Task Force (NTF) formulates a protocol.