Emergency Medicine is the medical specialty that focuses on the immediate decision making and action necessary
to prevent death or any further disability. It is primarily hospital emergency department based, but with extensive
pre-hospital responsibilities for emergency medical systems.

The emergency physician provides immediate initial recognition, evaluation, care and disposition of a generally
undifferentiated population of patients in response to acute illness and injury. The care provided by the emergency
physician is episodic in nature and involves a full spectrum of physical and behavioral conditions.

from American Board of Emergency Medicine,
http://www.abem.org/def.htm