On television, cardiopulmonary resuscitation (CPR) is like the Fonz hitting the jukebox on Happy Days: whack a dying person in the right spot and his heart will start beating again. However, this hardly ever works in real life, and it isn’t actually the point of administering CPR. The real goal here is to buy some valuable time until it’s possible to revive a normal heart beat, typically using an electric jolt from a defibrillator.
The cells in your body need oxygen to convert food into usable energy. Your heart delivers the goods. It pumps oxygenated blood from the lungs out to the body, and pumps de-oxygenated blood back to the lungs. If your heart isn’t pumping sufficient blood – a condition called cardiac arrest – your body’s cells will fail. Most significantly, your brain cells (neurons) will start dying four to six minutes after cardiac arrest begins.
Ten minutes without resuscitation efforts and the chances of revival are almost nil. The basic idea of CPR is to hold off death by manually forcing the victim’s lungs and heart to provide oxygenated blood to the brain. Exhaling air into the victim’s lungs provides the necessary oxygen, and regularly compressing the chest forces the heart to pump blood.