2. PUMP

If the victim is still not breathing normally, coughing or moving, begin chest compressions. Push down in the center of the chest 2 inches 30 times. Pump hard and fast at the rate of at least 100/minute, faster than once per second.
3. BLOW
Tilt the head back and lift the chin. Pinch nose and cover the mouth with yours and blow until you see the chest rise. Give 2 breaths. Each breath should take 1 second.
CONTINUE WITH 30 PUMPS AND 2 BREATHS UNTIL HELP ARRIVES
NOTE: This ratio is the same for one-person & two-person CPR. In two-person CPR the person pumping the chest stops while the other gives mouth-to-mouth breathing.
What complications can occur?
Vomiting is the most frequently encountered complication of CPR. If the victim starts to vomit, turn the head to the side and try to sweep out or wipe off the vomit. Continue with CPR.
The spread of infection from the victim to the rescuer is exceedingly rare. Most cardiac arrests occur in people's homes - relatives or friends will be the ones needing to do CPR. Even CPR performed on strangers has an exceedingly rare risk of infection. There is NO documentation of HIV or AIDS ever being transmitted via CPR.
What about checking for a pulse?
Checking The Pulse
The pulse check is no longer taught or expected of laypersons. Instead, if there is no response after two mouth-to-mouth breaths, begin to pump on the chest. Please note that the pulse check is still expected of health care providers.
CPR IN TWO SIMPLE STEPS - HANDS-ONLY CPR
This method of CPR was recommended by the AHA in 2010. It is intended for bystanders untrained in CPR. It is also recommended for situations when the rescuer is unable or unwilling to provide mouth-to-mouth ventilations.
1. CALL

Check the victim for unresponsiveness. If the person is not responsive and not breathing or not breathing normally, call 911 and return to the victim. In most locations the emergency dispatcher can assist you with CPR instructions.
2. PUMP


Begin chest compressions. Push down in the center of the chest 2 inches and keep doing it. Pump hard and fast at the rate of at least 100/minute, faster than once per second.
CONTINUE UNTIL HELP ARRIVES
Adopted FROM: http://depts.washington.edu/learncpr/quickcpr.html