Emergency medicine is a medical specialty involving care for undifferentiated, unscheduled patients with potentially serious acute illnesses or injuries that require immediate medical attention. While not usually providing long-term or continuing care, emergency physicians undertake the necessary investigations and interventions to diagnose patients in the acute phase, to liaise with physicians from other specialities, and to resuscitate and stabilize those who are seriously ill or injured. Emergency physicians generally practice in hospital emergency departments, pre-hospital settings via emergency medical services, and intensive care units, but may also work in primary care settings such as urgent care clinics.