CPR is a lifesaving procedure that is performed when someone's breathing or heartbeat has stopped, as in cases of electric shock, drowning, or heart attack. CPR is a combination of:

• Rescue breathing, which provides oxygen to a person's lungs.
• Chest compressions, which keep the person's blood circulating.

Permanent brain damage or death can occur within minutes if a person's blood flow stops. Therefore, you must continue these procedures until the person's heartbeat and breathing return, or trained medical help arrives.

CPR can be lifesaving, but it is best performed by those who have been trained in an accredited CPR course. The procedures described here are not a substitute for CPR training. (See www.americanheart.org for classes near you.)

Time is very important when dealing with an unconscious person who is not breathing. Permanent brain damage begins after only 4 minutes without oxygen, and death can occur as soon as 4 - 6 minutes later.

When a bystander starts CPR before emergency support arrives, the person has a much greater chance of surviving. Nevertheless, when most emergency workers arrive at a cardiac arrest, they usually find no one giving CPR.

Machines called automated external defibrillators (AEDs) can be found in many public places, and are available for home use. These machines have pads or paddles to place on the chest during a life-threatening emergency. They use computers to automatically check the heart rhythm and give a sudden shock if, and only if, that shock is needed to get the heart back into the right rhythm.

When using an AED, follow the instructions exactly.

In adults, major reasons that heartbeat and breathing stop include:

• Drug overdose
• Excessive bleeding
• Heart disease (heart attack or abnormal heart rhythm)
• Infection in the bloodstream (sepsis)
• Injuries and accidents

• No breathing or difficulty breathing (gasping)
• No pulse
• Unconsciousness

The following steps are based on instructions from the American Heart Association.

1. Check for responsiveness. Shake or tap the person gently. See if the person moves or makes a noise. Shout, "Are you OK?"
2. Call 911 if there is no response. Shout for help and send someone to call 911. If you are alone, call 911 and retrieve an AED (if available), even if you have to leave the person.
3. Carefully place the person on their back. If there is a chance the person has a spinal injury, two people should move the person to prevent the head and neck from twisting.
4. Open the airway. Lift up the chin with two fingers. At the same time, tilt the head by pushing down on the forehead with the other hand.
5. Look, listen, and feel for breathing. Place your ear close to the person's mouth and nose. Watch for chest movement. Feel for breath on your cheek.
6. If the person is not breathing or has trouble breathing:
   • Cover their mouth tightly with your mouth.
   • Pinch the nose closed.
   • Keep the chin lifted and head tilted.
   • Give two rescue breaths. Each breath should take about a second and make the chest rise.
7. Perform chest compressions:
   • Place the heel of one hand on the breastbone -- right between the nipples.
   • Place the heel of your other hand on top of the first hand.
   • Position your body directly over your hands.
   • Give 30 chest compressions. These compressions should be FAST and hard. Press down about 2 inches into the chest. Each time, let the chest rise completely. Count the 30 compressions quickly: "1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30, off."
8. Give the person 2 more breaths. The chest should rise.
9. Continue CPR (30 chest compressions followed by 2 breaths, then repeat) until the person recovers or help arrives. If an AED for adults is available, use it as soon as possible.

If the person starts breathing again, place them in the recovery position. Periodically re-check for breathing until help arrives.

• If the person has normal breathing, coughing, or movement, DO NOT begin chest compressions. Doing so may cause the heart to stop beating.
• Unless you are a health professional, DO NOT check for a pulse. Only a health care professional is properly trained to check for a pulse.

• If you have help, tell one person to call 911 while another person begins CPR.
• If you are alone, as soon as you determine that the person is unresponsive, call 911 immediately. Then begin CPR.

To avoid injuries and heart problems that can lead to cardiac arrest:

• Eliminate or reduce risk factors that contribute to heart disease, such as cigarette smoking, high cholesterol, high blood pressure, obesity, and stress.
• Get plenty of exercise.
• See your doctor regularly.
• Always use seat belts and drive safely.
• Avoid using illegal drugs.

Emergency Cardiovascular Care Committee, Subcommittees, and Task Forces of the American Heart Association. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2005;112(24 Suppl):IV1-203.

Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th Ed. St. Louis, MO: Mosby; 2002;64-82.