CPR (cardiopulmonary resuscitation) is an emergency procedure for a person whose heart has stopped. It consists of
- Rescue breathing, to get oxygen to the lungs
- Chest compressions, to keep blood circulating
When blood flow or breathing stops, seconds count. Permanent brain damage or death can happen quickly. CPR can help keep oxygen flowing through a victim's body when the heart has stopped until emergency medical help arrives. Although it can buy time, it is not sufficient to keep the person alive for an extended period and despite the name is unlikely to revive them without additional medical intervention.
CPR is a rather violent procedure, unlike how it is portrayed in television shows, and usually causes significant secondary injuries, especially to the victim's rib cage. If performed improperly, not only will it be ineffective, but the damage can be severe. As such, it is only performed as a last resort. Therefore, you should not try CPR unless you have had training - if it is done incorrectly or when not absolutely necessary, it will almost certainly do more harm than good.