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Cardiopulmonary resuscitation (CPR): First aid

Remember to spell C-A-B

The American Heart Association uses the letters C-A-B to help people remember the order to perform the steps of CPR.

  • C: compressions
  • A: airway
  • B: breathing

Compressions: Restore blood flow

Compressions means you'll use your hands to push down hard and fast in a specific way on the person's chest. Compressions are the most important step in CPR. Follow these steps for performing CPR compressions:

  1. Put the person on his or her back on a firm surface.
  2. Kneel next to the person's neck and shoulders.
  3. Place the lower palm (heel) of your hand over the center of the person's chest, between the nipples.
  4. Place your other hand on top of the first hand. Keep your elbows straight and position your shoulders directly above your hands.
  5. Push straight down on (compress) the chest at least 2 inches (5 centimeters) but no more than 2.4 inches (6 centimeters). Use your entire body weight (not just your arms) when doing compressions.
  6. Push hard at a rate of 100 to 120 compressions a minute. The American Heart Association suggests performing compressions to the beat of the song "Stayin' Alive." Allow the chest to spring back (recoil) after each push.
  7. If you haven't been trained in CPR, continue chest compressions until there are signs of movement or until emergency medical personnel take over. If you have been trained in CPR, go on to opening the airway and rescue breathing.

Airway: Open the airway

If you're trained in CPR and you've performed 30 chest compressions, open the person's airway using the head-tilt, chin-lift maneuver. Put your palm on the person's forehead and gently tilt the head back. Then with the other hand, gently lift the chin forward to open the airway.

Breathing: Breathe for the person

Rescue breathing can be mouth-to-mouth breathing or mouth-to-nose breathing if the mouth is seriously injured or can't be opened. Current recommendations suggest performing rescue breathing using a bag-mask device with a high-efficiency particulate air (HEPA) filter.

  1. After opening the airway (using the head-tilt, chin-lift maneuver), pinch the nostrils shut for mouth-to-mouth breathing and cover the person's mouth with yours, making a seal.
  2. Prepare to give two rescue breaths. Give the first rescue breath — lasting one second — and watch to see if the chest rises.
  3. If the chest rises, give a second breath.
  4. If the chest doesn't rise, repeat the head-tilt, chin-lift maneuver and then give a second breath. Thirty chest compressions followed by two rescue breaths is considered one cycle. Be careful not to provide too many breaths or to breathe with too much force.
  5. Resume chest compressions to restore blood flow.
  6. As soon as an automated external defibrillator (AED) is available, apply it and follow the prompts. Give one shock, then resume chest compressions for two more minutes before giving a second shock. If you're not trained to use an AED, a 911 operator or another emergency medical operator may be able to give you instructions. If an AED isn't available, go to step 5 below.
  7. Continue CPR until there are signs of movement or emergency medical personnel take over.