One reason cardiac arrest victims don't always survive is that bystanders are reluctant to do CPR, either because they don't want to do mouth-to-mouth or are afraid that they'll make a mistake. "Having a bystander intervene before emergency personnel arrives can double or even triple the chances of survival," says Michael Sayre, MD , chairman of the American Heart Association emergency cardiovascular care committee. Good news: CPR is now pretty much foolproof (and ick-proof), since guidelines no longer recommend that untrained laypeople perform mouth-to-mouth or check for breathing. The next time someone collapses and appears to be unconscious, here's what to do:
Step 1: Call 911 ASAP—or have someone else nearby do it. The sooner the person gets emergency care, the better his chances of survival.
Step 2: Get into position. Kneel down next to the person and place your hands on top of each other (palms down) in the middle of his chest. Don't worry about finding a specific spot; just aim for the center of his chest.
Step 3: Start chest compressions. Push down repeatedly with your hands as hard and as fast as you can, focusing on pressing with the heel of your palms. Ideally you should be doing at least 100 compressions per minute. Pushing on the chest squeezes the heart between the breastbone and backbone (mimicking its natural pumping motion) and raises pressure inside the chest. In turn, this pushes blood to the brain and provides oxygen to the arteries of the heart.
Step 4: Continue compressions until emergency help arrives with a defibrillator. They can then determine whether a shock, which reboots the heart, is needed or not.