Cardiopulmonary resuscitation (CPR) aims to restore, or support, function of the heart and lungs in victims who are not breathing and do not have a pulse. A combination of chest compressions and mouth-to-mouth rescue breathing performed during CPR assists the circulation of blood and oxygen throughout the body to sustain organs and tissues. The American Heart Association estimates that early, effective CPR can double a victim's chance of survival.
Circulation
When the heart stops pumping or begins to pump insufficiently, blood is unable to circulate throughout the body. A victim requiring CPR does not have an adequately functioning heart and is unable to circulate oxygen-rich blood without support. During CPR, chest compressions apply direct pressure to a victim's chest and are delivered at a rate of 100 compressions per minute. During each compression, blood is manually forced to circulate to the heart, brain, tissues and other organs a little bit at a time, thus feeding the body until either the heart starts pumping, or more advanced heart care is provided. Without chest compressions, organs and tissues will die, resulting in death of the victim.
Oxygenation
Oxygen is supplied to a victim during CPR both directly to the lungs, and also through circulation of oxygen-rich blood. Without oxygen, brain and tissue cells begin to die rapidly. Both components of CPR--chest compressions and rescue breathing--work in tandem to deliver oxygen in attempt to support life until further medical intervention becomes available. Mouth-to-mouth rescue breathing delivers oxygen directly to the victim's respiratory system, assisting to replace stores of oxygen needed to keep organs alive, while chest compressions circulate oxygenated blood throughout the system.
Organ Donation
An alternate advantage of CPR is the ability to keep organs alive that are intended for anatomical gifting if a victim has died. The New England Journal of Medicine July 2007 issue of "Perspectives" reports that organs, such as the kidney, liver, lungs and pancreas, can be supported with continuous, effective CPR to supply blood and oxygen until advanced organ preservation methods can be performed.
Survival
CPR has the main advantage of saving lives. The American Heart Association estimates a victim's chance of survival drops 7 percent to 10 percent for every minute of delay in receiving CPR, while those who receive early CPR have a 50 percent better chance of long-term survival. Additionally, victims who receive immediate CPR often respond better to electrical stimulation to the heart defibrillation, which can often restart the heart. CPR essentially "primes" the heart by providing circulation, which allows defibrillation to work more effectively and with better outcomes.
