How to Perform CPR: A Step-by-Step Guide for Emergencies

Cardiac arrest can happen anywhere — at home, at work, or in a public space. When someone's heart stops beating effectively, every minute without intervention reduces their chances of survival. CPR (cardiopulmonary resuscitation) keeps oxygenated blood moving to the brain and vital organs until professional help arrives. You don't need to be a medical professional to make a difference. Here's what you need to know. 🫀

What CPR Does — and Why It Matters

CPR works by manually compressing the chest to pump blood out of the heart, then allowing it to refill. Combined with rescue breaths (in some forms of CPR), this circulation keeps oxygen reaching the brain during the critical window before emergency responders arrive.

Without intervention, brain damage can begin within minutes of cardiac arrest. Bystander CPR — performed by whoever is nearby — is widely recognized as one of the most important factors in survival outcomes. The skill is learnable, and even imperfect CPR is significantly better than no CPR.

Recognize When CPR Is Needed

Before starting CPR, confirm the situation warrants it. CPR is appropriate when a person is:

• Unresponsive — they don't react to tapping their shoulders and calling their name
• Not breathing normally — no chest rise, or only occasional gasping (called agonal breathing)
• Pulseless — though checking for a pulse accurately is difficult for non-trained bystanders; if in doubt, begin CPR

Do not perform CPR on someone who is breathing normally and has a pulse. If the person is responsive or breathing, place them in the recovery position and monitor them while you call for help.

Step 1: Call for Help Immediately

Before or simultaneously with starting CPR, call emergency services (911 in the U.S.) or instruct someone nearby to call. If an AED (automated external defibrillator) is available, send someone to retrieve it. Time matters — professional help needs to be on the way.

If you're alone, use speakerphone so your hands remain free.

Step 2: Position the Person Correctly

Lay the person on their back on a firm, flat surface. Kneel beside them at chest level. If they're face-down, carefully roll them onto their back, supporting the head and neck as you do.

Step 3: Perform Chest Compressions ⚡

This is the most critical part of CPR. Quality compressions keep blood circulating.

Hand placement:

• Place the heel of one hand on the center of the chest — on the lower half of the breastbone (sternum)
• Place your other hand on top, interlacing your fingers
• Keep your fingers lifted so only the heel of your hand contacts the chest

Compression technique:

• Keep your arms straight and position your shoulders directly above your hands
• Push down hard and fast — aim for enough depth to compress the chest significantly (roughly 2–2.4 inches for adults, though focusing on firm, rhythmic pressure is more practical for untrained bystanders)
• Allow the chest to fully recoil between compressions — don't lean on the chest
• Aim for a rate of 100–120 compressions per minute — roughly the beat of the song "Stayin' Alive" by the Bee Gees, which is a commonly cited memory aid for pacing

Minimize interruptions. Pausing compressions, even briefly, reduces their effectiveness.

Step 4: Rescue Breaths (If Trained and Willing)

Hands-only CPR — compressions without rescue breaths — is recommended by many health authorities for untrained bystanders or those uncomfortable with mouth-to-mouth. It is effective and widely encouraged over doing nothing.

If you are trained in CPR and choose to give rescue breaths, the standard adult ratio is 30 compressions followed by 2 breaths.

To give a rescue breath:

• Tilt the head back gently and lift the chin to open the airway
• Pinch the nose closed
• Create a seal over the mouth and give a breath lasting about 1 second — just enough to see the chest rise
• Allow the chest to fall, then give the second breath
• Resume compressions immediately

If the chest doesn't rise on the first breath, re-tilt the head and try once more before returning to compressions. Do not spend excessive time on breaths — compressions take priority.

Step 5: Use an AED as Soon as One Is Available

An AED is a portable device that analyzes heart rhythm and can deliver an electric shock to restore a normal heartbeat. AEDs are designed for untrained users and walk you through every step with voice instructions.

• Turn it on and follow the prompts
• Attach the pads to bare skin as shown in the diagrams
• Let the AED analyze — make sure no one is touching the person
• Deliver the shock if advised, then immediately resume CPR

AEDs do not shock a normal heart — they only advise a shock when the rhythm warrants it. Using one is safe for bystanders.

CPR Varies by Age Group

The core principles are the same, but technique adjusts for smaller bodies:

For infants and children, rescuers who are trained typically use a 30:2 ratio for a single rescuer, and 15:2 when two trained rescuers are present.

Hands-Only vs. Full CPR: Which Applies?

The underlying cause of the emergency affects which approach is most beneficial — which is one reason formal CPR training provides important context beyond this overview.

When to Stop CPR

Continue CPR until:

• Emergency medical services arrive and take over
• The person shows obvious signs of life (normal breathing, movement, responsiveness)
• An AED advises you to pause for analysis or a shock
• You are physically unable to continue

Why Formal Training Still Matters 🎓

This guide gives you a working understanding of CPR, but hands-on training through organizations like the American Heart Association or the American Red Cross provides practice on mannequins, real-time feedback on compression depth and rate, and confidence under pressure. Training also covers variations for specific scenarios, two-rescuer techniques, and how to manage airway obstructions.

Certification courses typically run a few hours, and many workplaces, community centers, and schools offer them regularly. Refresher courses are recommended periodically, as guidelines are updated as new evidence emerges.

What you do in the first few minutes of a cardiac emergency can be the difference — knowing the steps in advance means you won't have to figure it out when it counts.