Agonal respiration goes by many names, including gasping respiration, Cheyne-Stokes respiration and death rattle. As the name indicates, these breaths (respirations) sound as though they are causing agony.
When agonal respirations occur, the end of life is near. It could be within minutes, in the case of cardiac arrest, or as long as weeks in the case of some diseases such as cancer.
Agonal respirations are a sign that the body is not receiving enough oxygen. In the case of cardiac arrest, agonal breathing is an indication to start CPR (cardiac pulmonary resuscitation).
While the sound of agonal respirations makes people think that the person must be in agony, there is no hard scientific evidence to support this.
According to the American Heart Association, "Many times people who suddenly collapse from cardiac arrest will make a gasping noise that can be mistaken for breathing. This is called agonal breathing or gasping. It can sound like gasping, snorting, gurgling, moaning or labored breathing. Remember, gasping is not breathing."
Many times people think that someone having agonal respirations is still breathing, when in fact they are not. For cardiac arrest victims, this may mean the difference between life and death.