When someone’s heart stops or they stop breathing, every second really counts. CPR keeps blood and oxygen moving until medical help arrives, giving the person a better shot at survival.
Knowing what to do in those first moments can turn a terrifying emergency into a life-saving response.
In an emergency, you just can’t afford to freeze up. Spotting the signs of cardiac arrest, calling for help, and jumping into chest compressions right away can mean the difference between life and death.
The steps aren’t complicated, but you’ve got to use the right technique for them to work.
This guide covers how to assess the situation, stay safe, and perform CPR with confidence. From hand placement to using an AED, each section breaks down what to do and why it matters, so anyone can step up when it’s needed most.
Recognizing a Cardiac Emergency
A person in sudden cardiac arrest quickly loses the ability to breathe normally or respond. If bystanders recognize this fast, they can act immediately and keep blood flowing to vital organs until help gets there.
Signs of Sudden Cardiac Arrest
Sudden cardiac arrest can strike without warning. Usually, the first sign is a sudden collapse—the person might fall and become motionless.
They’ll almost always show no normal breathing. Sometimes, you’ll hear weird gasping sounds called agonal breaths, but that’s not real breathing.
They’ll also be unresponsive. You won’t get a word, a blink, or any reaction if you touch or talk to them.
Other signs might show up:
- Skin turning pale or bluish, especially around the lips or fingertips
- No pulse you can find (if you know how to check)
- Eyes that just look fixed or blank
If you see these symptoms, the heart has stopped working right, and CPR should begin immediately.
Assessing Responsiveness and Breathing
Before you start CPR, check if the person is awake and breathing normally.
First, make sure the area’s safe for you and the victim. Tap their shoulders and shout, “Are you okay?”
If there’s no response, shout for help and tell someone to call emergency services and grab an AED if there’s one around.
Next, check their breathing. Watch for chest movement, listen for breath sounds, and feel for air from their mouth or nose. Don’t spend more than 10 seconds on this.
If they’re not breathing or just gasping, that’s cardiac arrest. Unless you’re trained and super quick, don’t waste time trying to find a pulse.
When to Start CPR
Start CPR immediately if the person doesn’t respond and isn’t breathing normally. Every second you wait lowers their odds.
Put the heel of one hand in the center of their chest, stack your other hand on top, and lock your elbows. Push hard and fast—100–120 compressions per minute and about 2 inches (5 cm) deep for adults.
Let the chest rise all the way between compressions. If you know how, give 30 compressions and then 2 breaths. If you’re not trained, just keep going with hands-only CPR until help or an AED arrives.
Ensuring Scene Safety and Calling for Help
Before you jump in, make sure the area’s safe and that someone’s calling for help. You don’t want to end up as another victim.
Checking for Environmental Hazards
You’ve got to pause and scan the area before moving in. A safe approach keeps you from becoming a casualty.
Watch out for things like:
- Traffic from nearby roads
- Power lines or anything electrical
- Fire, smoke, or fumes from chemicals or fuel
- Unstable buildings or falling debris
- Aggressive people or unruly crowds
If there’s any risk, don’t go in until it’s dealt with. Sometimes, you’ll have to move the victim if things get dangerous, like in a fire or rising water.
The American Heart Association (AHA) says scene safety comes first, even if it means a short delay. It’s better than getting hurt yourself.
Contacting Emergency Services
Once you know it’s safe, call for professional help right away.
If others are around, pick someone and tell them directly:
- Point to a person and tell them to call 911
- Make sure they come back and confirm they did it
If you’re alone, use your phone on speaker so you can stay with the victim while you call.
When it comes to CPR, minutes matter. Getting emergency medical services on the way fast means trained help and equipment are coming.
Providing Essential Information to Dispatch
Give the dispatcher clear info so they can send the right help. You’ll want to share:
- Exact location – address, landmarks, or GPS if you can
- What’s happening – cardiac arrest, unresponsive person, or severe bleeding
- Victim details – age, sex, and what shape they’re in right now
- What you’re doing – CPR started, AED in use, bleeding controlled
Listen to the dispatcher’s instructions. A lot of them are trained to walk you through CPR, step by step. Try to speak slowly and stay calm—it really helps.
Preparing to Perform CPR
Before you start CPR, make sure the person is lying flat on a sturdy surface and their airway is clear. Good body position and airway management help you give effective compressions and breaths.
Positioning the Victim
Lay the person on their back on a firm, flat surface like the floor or ground. Soft or uneven spots just don’t work for compressions.
Kneel right beside their chest so your shoulders are over your hands. That way, you can push straight down without bending your elbows.
If they’re face down, roll them onto their back gently but firmly. Support their head and neck as you roll to avoid making any injury worse.
Keep the head, neck, and spine lined up, especially if there’s a chance of neck injury.
Key points:
- Back flat on something solid
- Knees close to the body
- Shoulders right above your hands for compressions
Opening the Airway
Tilt the head back a bit by putting one hand on the forehead and the other under the chin. This head-tilt, chin-lift move gets the tongue out of the way.
If you think there’s a neck injury, use the jaw-thrust instead and keep the head straight.
Check for stuff in the mouth. Only do a finger sweep if you actually see something you can grab easily.
A clear airway means rescue breaths go to the lungs, not the stomach.
Airway steps:
- Head tilt and chin lift
- Look for obstructions
- Use jaw-thrust if you suspect a neck injury
Performing High-Quality Chest Compressions
Chest compressions keep blood moving to the brain and heart during cardiac arrest. Good technique means proper hand placement, consistent depth and rate, and keeping pauses short to maintain circulation.
Hand Placement and Body Position
Put the heel of one hand in the center of the chest, right on the lower half of the sternum. Place your other hand on top and interlace your fingers.
Keep your arms straight, with your shoulders directly above your hands. That way, you’re using your body weight instead of just your arms.
Kneel close enough to the patient to stay steady, but not so close you can’t extend your arms fully.
A good posture helps you keep going without getting tired fast. Don’t move your hands around during compressions—it makes them less effective and could cause injury.
Compression Depth and Rate
For adults, push down at least 2 inches (5 cm) but not more than 2.4 inches (6 cm). For kids, aim for about a third of the chest’s depth.
Keep the pace at 100 to 120 compressions per minute. Some people use the beat of certain songs to help stay on track.
Let the chest come all the way back up after each push. This lets the heart refill with blood.
Don’t lean on the chest between compressions—it stops full recoil and cuts down blood flow. If you’ve got a feedback device, use it to help keep your depth and rate on target.
Minimizing Interruptions
Pausing compressions lowers survival chances. Try to keep breaks under 10 seconds.
If you’re giving rescue breaths, do them quickly so you don’t stop compressions for long.
If there’s more than one rescuer, switch every couple of minutes to avoid getting tired. That keeps compression quality up.
Get equipment like an AED ready without stopping compressions for long. Only pause when you absolutely have to, like for a shock or to check for signs of life.
Delivering Rescue Breaths
Rescue breaths give oxygen to someone who can’t breathe on their own. They work with chest compressions to keep the brain and organs alive until the pros arrive. You need the right technique to make sure air gets to the lungs.
Mouth-to-Mouth Technique
For mouth-to-mouth, make a seal over the victim’s mouth to blow air into their lungs. Tilt the head back a bit and lift the chin to open the airway.
Pinch the victim’s nose shut so air doesn’t escape. Take a normal breath, cover their mouth with yours, and blow for about one second. You want to see the chest rise, not blow too hard.
If you don’t see the chest rise, adjust the head and try again. Don’t blow too fast or hard, or you could push air into the stomach.
If you have a CPR face shield or mask, use it to cut down on disease risk and still get a good seal.
Ensuring Effective Ventilation
Effective breaths mean air’s getting to the lungs and helping oxygen exchange. Watch for the chest to rise each time you give a breath. That’s how you know the airway’s open and the breath is working.
If there’s no chest rise, the airway might be blocked. Do the head-tilt, chin-lift again and check for anything in the mouth.
Give breaths at the right rhythm—two after every 30 compressions in standard adult CPR. Each breath should last about one second, just enough to see the chest rise.
Don’t take too long between compressions and breaths. Quick, controlled transitions keep survival chances up.
Using an Automated External Defibrillator (AED)
An AED checks the heart rhythm and can give a shock if needed to get the heart beating right again during sudden cardiac arrest. Using one quickly and correctly can boost survival before the ambulance gets there.
Locating and Turning On the AED
You’ll often find AEDs in public spots—airports, schools, gyms, offices. They’re usually in marked wall cabinets or on stands where you can see them.
If one’s available, have someone grab the AED while you start CPR. The American Heart Association (AHA) says to turn it on as soon as you get it.
Most AEDs have a big power button or turn on when you open the lid. Once it’s on, it talks you through the steps with voice and pictures.
Keep the AED close to the person’s head and chest so the cables reach. Don’t wait for trained people—AEDs are made for anyone to use.
Attaching the Pads and Following Prompts
Bare the person’s chest and get rid of any clothing that’s in the way. If the skin’s wet, dry it so the pads stick.
Stick one pad on the upper right chest, just under the collarbone. Put the other on the lower left side, a few inches below the armpit. Follow the pictures on the pads.
If the chest is small and pads might touch, put one in the center of the chest and the other between the shoulder blades.
Plug in the pads if they’re not already connected. The AED will analyze the heart rhythm for you.
When the AED says “Clear,” make sure no one’s touching the person. If it tells you to, press the shock button.
Start CPR again right after the shock, or if no shock’s advised.
Continuing CPR Until Help Arrives
When someone goes into cardiac arrest, their body needs constant chest compressions and rescue breaths to keep oxygen flowing to the brain and other vital organs. If you stop too soon, you might lower their chances of surviving before trained responders arrive.
Repeating Compression and Breath Cycles
For adults, CPR uses a 30:2 ratio—thirty chest compressions, then two rescue breaths. Try to keep up a steady rhythm of 100–120 compressions per minute and push down at least two inches with each compression.
Keep your hands in place between compressions, and let the chest rise all the way back up. This gives the heart a chance to refill with blood before you press again.
Give rescue breaths that are slow and steady, about one second each, and watch for the chest to rise. If you don’t see the chest rise, tilt the head back and try again.
Try to avoid stopping, even for a moment. Short breaks can really drop blood flow to the brain. If you have an AED nearby, use it quickly, but get right back to CPR as soon as it delivers a shock or says not to.
When to Stop Performing CPR
Keep doing CPR without interruption until:
| Situation | Action |
|---|---|
| Trained medical help arrives | Let them take over care |
| The person shows signs of life | Stop compressions and watch their breathing |
| The person breathes normally | Move them into the recovery position |
| The rescuer can’t keep going | Ask another bystander for help |
| The scene gets unsafe | Try to move to safety if you can |
You might notice signs of life like purposeful movement, normal breathing, or even coughing. But if you only see the person gasping, that’s not normal breathing, so you need to keep going with CPR.
If someone else trained in CPR is there, you two can switch every couple of minutes. This helps keep compressions strong and steady until emergency services show up.