When someone collapses suddenly and stops breathing, the moments that follow can mean the difference between life and death. Knowing how to perform Cardiopulmonary Resuscitation (CPR) correctly can save a life before medical professionals arrive.

This step-by-step guide breaks down everything you need to know about performing CPR on an adult — including recognizing cardiac arrest, preparing the scene, administering chest compressions, using an AED, and understanding common mistakes to avoid.

Whether you’re a trained rescuer or a concerned bystander, this detailed guide will empower you to act confidently in an emergency.

Understanding CPR and Its Importance

What Is CPR?

CPR (Cardiopulmonary Resuscitation) is an emergency life-saving procedure performed when the heart stops beating. It combines chest compressions (to manually pump blood) and rescue breaths (to supply oxygen), helping maintain vital circulation until professional medical help arrives.

In simple terms, CPR keeps oxygen flowing to the brain and other organs — buying precious time during a sudden cardiac arrest (SCA).

Why CPR Matters

When the heart stops:

  • Brain cells begin to die within 4–6 minutes.
  • Permanent brain damage can occur after 8 minutes.
  • Without immediate action, death is almost certain.

Performing CPR can double or even triple a person’s chance of survival, especially if started immediately.

According to the American Heart Association (AHA), more than 350,000 out-of-hospital cardiac arrests occur in the U.S. each year — and most victims don’t receive bystander CPR. The outcome depends largely on how quickly someone steps up to help.

Recognizing When CPR Is Needed

Before starting CPR, you must quickly determine whether it’s necessary. Here’s how to recognize a cardiac arrest or medical emergency requiring CPR.

1. Check Responsiveness

  • Tap the person firmly on the shoulders.
  • Shout: “Are you okay?”
  • Look for any response, movement, or sound.

If there’s no response, proceed immediately to the next step.

2. Check Breathing

  • Tilt the head back slightly to open the airway.
  • Look for chest movement, listen for breathing sounds, and feel for air movement.
  • If the person is not breathing or is only gasping (agonal breathing), assume cardiac arrest.

3. Call for Help

  • Dial 911 (or your local emergency number) immediately.
  • If someone is nearby, ask them to call and get an AED (Automated External Defibrillator).
  • If you’re alone, put your phone on speaker mode so the emergency dispatcher can guide you through CPR.

Never delay CPR while waiting for help.

The ABCs of CPR (Updated Approach)

Traditionally, CPR followed the A-B-C (Airway–Breathing–Circulation) order.
However, the AHA now recommends the C-A-B sequence — focusing on Chest Compressions first, as immediate circulation is critical.

C-A-B Steps:

  • C – Compressions
  • A – Airway
  • B – Breathing

Let’s go through each in detail.

During cardiac arrest, the heart can’t pump blood effectively. Chest compressions manually circulate blood to vital organs, keeping them alive until normal heart rhythm returns.

Step 1: Chest Compressions

Why They’re Important

How to Perform Chest Compressions on an Adult

  • Position the Person
    • Lay the person flat on their back on a firm surface.
    • Kneel beside their chest.
  • Hand Placement
    • Place the heel of one hand on the center of the chest (lower half of the sternum, between the nipples).
    • Place your other hand on top, interlocking your fingers.
    • Keep your arms straight and shoulders directly above your hands.
  • Compression Technique
    • Push hard and fast — about 2 inches (5 cm) deep.
    • Allow the chest to recoil fully after each push.
    • Maintain a rate of 100–120 compressions per minute (like the beat of the song “Stayin’ Alive” by the Bee Gees).
    • Avoid leaning on the chest between compressions.
  • Count Aloud or Use Rhythm Cues
    • Counting helps maintain consistent speed and depth.
    • If you’re unsure of the rhythm, hum “Stayin’ Alive” or “Baby Shark” — both match the ideal tempo.

Compression Tips

  • If you feel or hear ribs crack, don’t stop — broken ribs are better than no circulation.
  • Use your upper body weight, not just your arms.
  • Keep compressions smooth, not jerky.

Step 2: Open the Airway

After 30 compressions, you’ll need to check the airway before giving rescue breaths.

  • Tilt the Head and Lift the Chin
    • Place one hand on the forehead and gently tilt the head back.
    • With your other hand, lift the chin forward.
    • This maneuver opens the airway by moving the tongue away from the back of the throat.
  • Check for Obstructions
    • Quickly look into the mouth for vomit, blood, or foreign objects.
    • If visible, sweep it out carefully with a finger — but don’t perform blind sweeps, as this could push the object deeper.

Step 3: Give Rescue Breaths

If you are trained and willing, combine compressions with rescue breaths. If you’re untrained, continue with hands-only CPR (compressions only).

How to Give Rescue Breaths

  1. After 30 compressions, pinch the nose shut.
  2. Take a normal breath, cover their mouth completely with yours to make a seal.
  3. Blow steadily for about 1 second, watching the chest rise visibly.
  4. Deliver 2 rescue breaths.
  5. Immediately continue 30 compressions.

This cycle (30 compressions + 2 breaths) is repeated continuously.

If the chest doesn’t rise during a breath:

  • Recheck the head tilt and chin lift.
  • Ensure your seal is tight.
  • If it still doesn’t work, return to compressions.

Hands-Only CPR (For Untrained Rescuers)

If you’re not comfortable giving rescue breaths, that’s okay — hands-only CPR is still highly effective for adults.

Hands-Only CPR Steps:

  • Call 911 and put your phone on speaker.
  • Begin chest compressions immediately:
    • Push hard and fast at 100–120 per minute.
    • No rescue breaths needed.
  • Continue until:
    • The person starts breathing,
    • An AED is ready to use, or
    • Medical help arrives.

Research shows that hands-only CPR can significantly increase survival rates for adult cardiac arrest victims.

Using an AED (Automated External Defibrillator)

What Is an AED?

An AED is a portable device that delivers an electric shock to restore a normal heart rhythm during cardiac arrest. It’s designed for anyone to use, even without medical training.

How to Use an AED: Step-by-Step

  • Turn on the AED
    • Open the lid or press the power button.
    • The device will give voice instructions.
  • Expose the Chest
    • Remove clothing and dry the chest if wet.
    • Shave excess hair only if it prevents pad adhesion.
  • Apply the Pads
    • Place one pad on the upper right chest (below the collarbone).
    • Place the second pad on the lower left side (below the armpit).
  • Follow AED Prompts
    • The AED will analyze the heart rhythm.
    • Make sure no one is touching the person during analysis.
  • Deliver the Shock (if advised)
    • The device will instruct you to press the shock button.
    • After delivering the shock, immediately resume CPR for 2 minutes before the next analysis.
  • Continue Until Help Arrives
    • Keep following AED prompts.
    • Do not remove the pads unless told to.

When to Stop CPR

Continue performing CPR until one of the following occurs:

  • Professional help arrives and takes over.
  • An AED becomes available and instructs you to stop.
  • The person shows signs of life — movement, breathing, or consciousness.
  • You are physically exhausted and cannot continue safely.
  • The scene becomes unsafe (e.g., fire, flood, or traffic hazard).

Common Mistakes to Avoid

Even small errors during CPR can reduce effectiveness. Here are the most common mistakes — and how to avoid them.

  • Shallow Compressions
    • Press at least 2 inches deep in adults.
    • Shallow compressions don’t circulate enough blood.
  • Incorrect Hand Placement
    • Stay in the center of the chest — between the nipples.
    • Avoid pressing on the ribs or upper chest.
  • Not Allowing Full Recoil
    • Let the chest return to its normal position after each compression.
    • Leaning reduces blood return to the heart.
  • Slow Compression Rate
    • Keep rhythm at 100–120 per minute.
    • Too slow = not enough blood flow.
    • Too fast = poor compression depth.
  • Delaying CPR for Rescue Breaths
    • Start compressions first — oxygen can wait; circulation cannot.
  • Stopping Too Soon
    • Continue until medical professionals take over or the person revives.

Dispatcher-Assisted CPR (DA-CPR)

If you ever call 911 for a cardiac emergency, the dispatcher can guide you through CPR in real-time.

These trained professionals:

  • Help you recognize cardiac arrest.
  • Give step-by-step voice instructions.
  • Count rhythm and timing for compressions.

Following their guidance can double or triple survival chances — even if you’ve never been trained in CPR before.

CPR for Special Situations

If the Person Vomits

  • Turn them onto their side briefly to clear the airway.
  • Then return to their back and resume compressions.

If the Person Has a Pacemaker

  • You may feel a small hard lump under the skin.
  • Place AED pads at least 1 inch away from it.

If the Person Is Pregnant

  • Perform CPR as usual but tilt her slightly to the left side to reduce pressure on major blood vessels.

If You Are Alone

  • Call 911 first, then start CPR immediately.
  • Use speakerphone for dispatcher guidance.

Why Every Second Counts

For every minute that passes without CPR:

  • The chance of survival decreases by 7–10%.
  • After 10 minutes, survival is unlikely without immediate intervention.

Starting CPR immediately can maintain life until paramedics arrive with advanced care.

Training and Certification

While anyone can perform CPR, formal training through certified courses ensures confidence and skill.

Recommended providers:

  • American Heart Association (AHA)
  • Red Cross
  • National Safety Council
  • Local hospitals and training centers

These classes often include:

  • Hands-on practice with mannequins.
  • AED usage.
  • Realistic cardiac arrest scenarios.

Most certifications are valid for 2 years and can be renewed easily.

The Psychological Barrier: Overcoming Fear

Many bystanders hesitate to perform CPR because they fear:

  • Doing it wrong
  • Hurting the victim
  • Legal consequences

Here’s the truth:

  • Any CPR is better than none.
  • You can’t make the situation worse if the heart has already stopped.
  • Good Samaritan Laws protect you from legal liability if you act in good faith.

Your quick action could save a life — possibly someone you love.

Post-CPR Care: What Happens Next

Once paramedics take over:

  • They’ll use advanced techniques like defibrillation, airway management, and medication.
  • The patient will be transported to the hospital for post-cardiac arrest care, which includes:
    • Oxygen therapy
    • Cooling therapy (to protect the brain)
    • Heart monitoring
    • Diagnosis of the cause of arrest

Your timely CPR ensures the patient reaches this stage with a beating heart and a chance at recovery.

Real-Life Example: A Heroic Rescue

In a crowded mall, a 45-year-old man collapses suddenly. A bystander, trained in CPR, immediately checks responsiveness, calls 911, and starts compressions.

Within minutes, security brings an AED. She follows voice prompts, delivers one shock, and resumes compressions.

By the time paramedics arrive, the man’s heart rhythm has returned.

Doctors later confirm: Without those first two minutes of CPR, he wouldn’t have survived.

This story illustrates the power of one person’s quick, confident action — and how CPR knowledge transforms ordinary people into lifesavers.

Conclusion

Cardiac arrest can happen anywhere — at home, at work, or on the street. The ability to perform CPR gives you the power to keep someone alive until professional help arrives.

Remember the essentials:

  • Check responsiveness and breathing.
  • Call 911 and get an AED.
  • Begin chest compressions immediately.
  • Give rescue breaths if trained.
  • Continue until help arrives or the person revives.

Every minute, every compression, and every ounce of courage counts.