ABC (Medicine)

ABC is a mnemonic used in medicine for the priority sequence of airway, breathing and circulation when assessing and treating a patient in an acute medical or trauma situation. It originated as a teaching aid for cardiopulmonary resuscitation, guiding a rescuer through clearing the airway, checking for breathing and supporting circulation with chest compressions. In 2010 the American Heart Association reordered the sequence to CAB, placing chest compressions first in cardiac arrest, and later variants such as ABCDE add exposure and examination, DR ABC adds danger and response, and the trauma protocol xABCDE places control of severe hemorrhage before airway management.