Agonal breathing is a shallow gasping respiratory sound that unresponsive victims in cardiac arrest and no pulse often make before the end of life.
Agonal breaths should prompt a rescuer to start CPR as an emergency treatment because agonal breathing is not related to the 'near death rattle' phenomenon.
Agonal respiration is characterized by abnormal, laboured, ineffective breathing and is usually caused by strokes (cerebral ischemia) or a severe lack of oxygen.
It requires immediate medical attention. The condition rapidly progresses to complete apnea and usually the final breaths before biological death.
Agonal respirations also occur in cases of cardiac arrest or cardiogenic shock. The abnormal breathing rhythm may go on for several minutes lasting long after the cessation of a heartbeat.