Emergency medicine is the medical specialty involving care for undifferentiated and unscheduled patients with illnesses or injuries requiring immediate medical attention. In their role as first-line providers, emergency physicians are responsible for initiating investigations and interventions to diagnose and/or treat patients in the acute phase (including initial resuscitation and stabilization), coordinating care with physicians from other specialities, and making decisions regarding a patient's need for hospital admission, observation, or discharge. 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.