CPR: Are we doing it wrong?
Some say just doing chest compressions might be easier and more reliable. And there are questions about where the defibrillator fits in.
Cardiac arrest means simply that the heart has stopped beating. Without that constant thumping in our chests, the 10 or so pints of blood that usually circulate through 60,000 miles of arteries and veins stop flowing — and bad things start to happen, fast. The lungs are not delivering fresh oxygen. Metabolic waste products pile up. The blood turns dangerously acidic.
The brain and nervous system react first because they're such ravenous consumers of oxygen, but soon other organ systems start to falter. If circulation isn't restored within four or five minutes, the brain shuts down completely and permanently. That's the definition of death.