Cardiopulmonary resuscitation, commonly called CPR, combines rescue breathing (one person breathing into another person) and chest compression into one lifesaving procedure. It is performed when a person has stopped breathing or a person's heart has stopped beating. When performed quickly enough, CPR can save lives in such emergencies as loss of consciousness, heart attacks or cardiac arrests, electric shock, drowning, excessive bleeding, drug overdose, and other conditions in which there is no breathing or no pulse.
The purpose of CPR is to bring oxygen to the victim's lungs and to keep blood circulating so oxygen gets to every part of the body. When a person is deprived of oxygen, permanent brain damage can begin in as little as four minutes and death can follow only minutes later. So the main objective is to intervene as soon as possible.
Table below represents the likelihood of brain damage or death and typical timing after the heart stopping.
| 0 to 4 minutes after exhibiting symptoms | Chances of Brain Damage Minimal |
| 4 to 6 minutes after exhibiting symptoms | Chances of Brain Damage Possible |
| 6 to 10 minutes after exhibiting symptoms | Chances of Brain Damage Likely |
| Greater than 10 minutes | Chances of Brain Death Likely |
There are three general symptoms that warrant immediate administration of CPR:
If one or more of these symptoms is present, perform CPR as soon as possible.