How to Perform Cardiopulmonary Resuscitation (CPR)

Disclaimer: This article is for informational purposes and is not intended as a substitute for an actual training course. Find a CPR class near you.


CPR Basics

How to check breathing when performing CPR

A person needing CPR will be collapsed on the ground, completely unresponsive, not breathing, and have no pulse.

  1. To determine if a person needs CPR the first thing to do is go over and slap them on the shoulders to try waking them up. Be forceful; make sure they aren’t simply unconscious or semiconscious.
  2. If they don’t show any sign of life immediately call 911, then check to see if they’re breathing.
  3. Tilt the person's head back by lifting their chin, and put your ear close to their nose and mouth to listen for breathing sounds. As you do this look at their chest to see if it rises and falls. Do this for no more than 10 seconds to make sure they’re not breathing.

It is unnecessary to check for a pulse for 2 reasons.

  1. The pulse can be weak or difficult to find.
  2. The person may be unconscious due to choking. In this case the proper treatment is CPR. See the section on choking below for more information.

How to Perform CPR

Before giving CPR check for severe bleeding. If the patient has major bleeding, CPR will only push more blood out of their body. Hemorrhage must be controlled before starting CPR.

CPR Adult Chest Compression Heart
Chest compressions
  1. After determining that the person needs CPR, roll them onto their back and begin chest compressions by kneeling to one side of the torso and placing the heel of one hand in the center of their chest right between the nipples.
  2. Place the heel of your 2nd hand on top of the first one and interlock your fingers.
  3. Lock your elbows straight and position yourself so you’re pushing straight down. Push hard and fast, keeping a pace of at least 100 beats per minute (bpm). For reference, the choruses to Stayin' Alive by the Beegees and Another One Bites the Dust by Queen are both 100 bpm.
  4. Give 30 chest compressions counting out loud and pushing at least 2 inches deep on every compression.
  5. Stop compressions to give 2 rescue breaths.
  6. Tilt the head back, and lift the chin up.
  7. Pinch the nose so that the air goes into their lungs and blow into their mouth for about 1 second making sure that the chest rises. If you have a disposable face barrier, place it as shown by the pictographic instructions on the barrier. If you have a pocket mask, you don’t have to pinch the nose since the mask covers both the nose and the mouth. 5 cycles of breaths and compressions should take 2 minutes.

Repeat the cycles of compressions and breaths until one of these things happens:

  1. The person shows signs of life, like breathing.
  2. Another trained responder shows up and takes over.
  3. An AED is ready to use.

CPR for Choking Victims

If the patient is conscious and choking, perform the Heimlich maneuver. See here for more details.

If the patient is unconscious due to choking, CPR can clear their airway. Administer compressions and breaths as normal until the person shows signs of life, a trained responder shows up and takes over, or an AED is ready to use.

If the patient drowned, it may also be helpful to lower the head below the lungs to drain the water while you perform CPR.

CPR Theory: What’s going on inside the body?

The goal of CPR is to artificially keep a person’s heart pumping and their lungs breathing until a defibrillator can be used to restart their heart.

Chest compressions use the rib cage to physically compress the heart and squeeze blood throughout the body as if the heart was still beating.

The average person’s heart beats about 1-2 times per second, but you breathe about 12 times per minute. That’s why 30 chest compressions are needed for every 2 breaths.

The rate of compressions simulates a normal heartbeat. A normal resting heartbeat is between 60 and 100 bpm, but that’s not the reason 100 bpm is recommended. Theoretically, faster compressions up to about 180 bpm would be ideal, but good quality compressions, where the rib cage is allowed to fully recoil, are more important than speed.

Your own endurance is also a major limiting factor. After about 2 minutes compression quality starts to get much worse regardless of your level of fitness.

At higher compression rates you will tire even faster. If there are several people who can rotate in to do compressions, then go ahead and speed up a bit.

How to Use a Portable Defibrillator

Portable automatic external defibrillators are so simple to use that 6th grade students with no training were able to defibrillate patients within 90 seconds[1]. They are used in conjunction with CPR.

CPR alone will not save a person’s life. When attaching the AED do NOT stop CPR if possible. Turn on the portable defibrillator and follow the spoken step-by-step instructions.

Defibrillation Electrode Position
  1. Open the person’s clothing to expose the bare chest.
  2. Place each pad on the spot indicated by the picture instructions. At this point stop CPR and the AED will analyze the patient’s heart rhythm.
  3. If the AED says “Shock Advised,” make sure nobody is touching the patient and press the shock button.
  4. If the AED says “No Shock Advised,” begin CPR again unless the paramedics take over or the patient shows signs of life.

On the Philips Heartstart Home/OnSite Defibrillator there is a blue informational button that will instruct you how to perform CPR and give you a metronome to keep pace for compressions.

After a while the AED will tell you to stop CPR, and it will analyze the patient again. It’s normal for the AED to deliver multiple shocks to the patient before the heart is restarted. Even if the AED works and the patient shows signs of life, do NOT remove the pads from the patient. The AED will continue to monitor their heart rate in case there is a problem.

AED Theory: What's Going on Inside the Body?

Your heart is a pump that circulates blood throughout your entire body. The power behind that pump is the heart muscles, but there's also a metronome that keeps the heart beating at a certain speed and rhythm. This metronome is an electrical pulse that tells your heart when to beat.

The electrical pulse is caused by a cluster of cells called the sinoatrial node at the top of the heart. When the sinoatrial node fires, an electrical pulse spreads out like a ripple from the top of the heart to the bottom causing the heart muscle fibers to contract as the pulse reaches them.

CPR training-03

During a cardiac arrest, the electrical signal might be scrambled. This means that instead of getting regular electrical pulses that ripple from the top of the heart to the bottom, you have random electrical signals happening all over the heart all the time.

When this happens the heart quivers but doesn't contract properly because all the little muscle fibers are no longer working together. This is called fibrillation, so the machine used to resuscitate people is called a defibrillator.

By shocking the heart a defibrillator resets the timing and allows the sinoatrial node to take over.

An AED can only help when the heart is fibrillating. If the heart is completely stopped, for instance, a portable defibrillator will not help. That's one reason why the defibrillator will say "analyzing rhythm" during CPR. It's checking for fibrillation.

Cardiac Arrest: What to Expect

CPR is not a gentle procedure; it’s pretty normal to break the patient's ribs, especially if they’re older or suffer from a disease like osteoporosis. Good, hard compressions are more important than possible broken ribs.

When a person’s ribs break there will be a snap or popping sound and the chest won’t rebound as strongly as it did. You won’t feel as much resistance on each compression. If someone needs CPR and you break their ribs they’ll probably still thank you for it, but make sure they actually need CPR before you start pounding on their chest.

Often times people vomit during CPR. A common reason is because pressure is being put on the stomach during chest compressions. If this happens, roll the patient's whole body to the side, so he can vomit without choking, then use a finger to clear anything lodged in his mouth. Once his mouth and airway are clear, begin with rescue breaths and resume CPR.

You will know when the AED shocks the patient because the patient will spasm. In this video you can see a person being shocked with an AED about 5 seconds in from where the video starts.

Real Life Examples of CPR

Example 1 This video is a good example of solid CPR compressions. Notice the speed and depth of each compression.

The firemen already have the AED pads on the patient when the video starts, but 1 minute into the video it cuts to an earlier clip that shows the team actually putting the pads on the patient.

When they put the AED pads on the patient the guy doing compressions never stops. He only stops to let his partner do rescue breaths and when the AED is analyzing the patient's heart rhythm. After they start compressions the patient vomits, so the team rolls him on his side and clears his mouth so he doesn't choke.

Example 2: In this case the CPR lasts for a long time. Several people switch out doing compressions as they get tired.

Notice the 1st guy doing compressions is counting out loud so that the guy doing rescue breaths is ready when he's done with each set. The 1st guy does good, deep compressions even if they are a little slow.

The 2nd guy is faster, but his compressions aren't as deep. When he pushes down his elbows bend causing his compressions to be sloppier. The girl (3rd person doing compressions) has weak compressions that aren't deep enough. With CPR it helps to be big and heavy, so you get good deep compressions.

CPR Tips

  1. New research shows that raising the legs during CPR causes increased blood flow to important organs like the brain, increasing the chance of survival[2].

Additional Resources

  1. How to choose a CPR manikin or dummy
  2. The 4 Best Portable Defibrillators and Which to Buy
  3. Cardiac Arrest Alert App


  1. U.S. Department of Labor Occupational Safety and Health Administration (2001). "Cardiac arrest a automated external defibrillators (AEDs)". OSHA Publication No. TIB 01-12-17.
  2. Zhang, Yanru et al. "Not Bad: Passive Leg Raising In Cardiopulmonary Resuscitation-A New Modeling Study". Frontiers in Physiology 7 (2017): n. pag. Web. 14 Jan. 2017.

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