When a victim experiences a cardiac arrest, sometimes you can see something, sometimes you can hear something. Sometimes you may see the victim foaming at the mouth. A condition called acute pulmonary edema caused by fluid leaking into the lungs because of the stopped heart rate and slowed lung function. Sometimes you hear gagging sounds which is a brain stem reflex. These gasping sounds occur because the organs are losing oxygen. Gasping sounds or "agonal breathing" is not normal breathing. If you hear gasping sounds, that victim is still in cardiac arrest and needs chest compressions.