If someone collapses and isn’t breathing normally, call 911 immediately and start pushing hard and fast on the center of their chest. Every minute without CPR drops their chance of survival significantly. When bystanders begin chest compressions within one minute, about 22% of people survive to leave the hospital. Wait ten minutes and that number falls to roughly 10%. Speed matters more than perfection.
How to Recognize Cardiac Arrest
Cardiac arrest looks like a sudden collapse. The person won’t respond when you tap their shoulders and shout. They’ll either stop breathing entirely or make irregular gasping sounds that can resemble snoring, gurgling, or moaning. These gasps are a survival reflex triggered by the brain, not real breathing. Bystanders frequently mistake them for normal breathing and delay calling for help, which costs critical time. If someone collapses, is unresponsive, and isn’t breathing normally, treat it as cardiac arrest.
This is different from a heart attack. A heart attack is a circulation problem where a blocked artery cuts off blood flow to part of the heart. The person is usually conscious and may complain of chest pain, shortness of breath, or nausea. Cardiac arrest is an electrical problem: the heart suddenly stops pumping altogether, the person loses consciousness, and they have no pulse. A heart attack can trigger cardiac arrest, but they’re not the same event and they require different responses.
Step 1: Call 911 and Get an AED
The moment you confirm the person is unresponsive and not breathing normally, call 911 or tell someone nearby to call. If there are multiple bystanders, point directly at one person and tell them to call. Point at another and send them to find an AED (automated external defibrillator). Many public buildings, gyms, airports, and schools have them mounted on walls, often in bright-colored cases. If you’re alone, put your phone on speaker so you can talk to the dispatcher while you start compressions.
Step 2: Start Chest Compressions
Place the heel of one hand on the center of the person’s chest, between the nipples. Stack your other hand on top and interlace your fingers. Lock your elbows, position your shoulders directly above your hands, and push straight down at least 2 inches deep. Push at a rate of 100 to 120 compressions per minute. That’s roughly the tempo of the song “Stayin’ Alive.” Let the chest come all the way back up between each compression.
This is physically demanding. If someone else is nearby, switch off every two minutes to keep the compressions strong and deep. Weak or shallow compressions don’t move enough blood. Don’t stop compressions except to use an AED or switch with another person.
If you’re not trained in CPR or aren’t comfortable giving rescue breaths, hands-only CPR (continuous chest compressions without mouth-to-mouth) is effective for adults and is what the American Heart Association recommends for untrained bystanders. If you are trained and willing, give two rescue breaths after every 30 compressions.
Step 3: Use an AED as Soon as One Arrives
AEDs are designed for people with no medical training. Turn it on and it will talk you through every step with voice prompts. Here’s what to expect:
- Expose the chest. Remove or cut away clothing. If the chest is wet, wipe it dry.
- Attach the pads. Place one pad on the upper right side of the chest, below the collarbone. Place the other on the lower left side, a few inches below the armpit. Peel-and-stick diagrams on the pads show you exactly where they go.
- Let the AED analyze. The machine will tell everyone to stand clear. Say “Clear!” loudly and make sure nobody is touching the person.
- Deliver the shock if prompted. The AED will only advise a shock if it detects a rhythm that can be corrected. Press the shock button when told to. If no shock is advised, resume chest compressions immediately.
If the pads might touch each other (on a very small person), place one pad on the center of the chest and the other on the back between the shoulder blades. After delivering a shock, go right back to chest compressions. Continue this cycle of CPR and AED checks until paramedics take over or the person starts breathing normally.
CPR for Children and Infants
For children (roughly age 1 through puberty), the technique is similar but rescue breaths matter more. Children’s cardiac arrests are more often caused by breathing problems than electrical failures, so compressions combined with breaths produce better outcomes than compressions alone. Use two hands for chest compressions on children, pressing to about one-third the depth of the chest. Give two breaths after every 30 compressions if you’re alone, or every 15 compressions if two rescuers are present.
For infants under one year old, use the heel of one hand or wrap both hands around the ribcage and press with your thumbs on the breastbone. Compress to about one-third the depth of the chest. The two-finger technique that was previously taught has been removed from guidelines because it doesn’t achieve adequate depth. As with children, combine compressions with rescue breaths.
Why Every Second Counts
A large U.S. study of witnessed cardiac arrests found that people who received CPR within two to three minutes were 9% less likely to survive than those who got it within one minute. At four to five minutes, the odds of survival dropped by 27%. The decline is steep and continuous. Each passing minute without blood flow causes irreversible damage to the brain and organs.
Defibrillation is equally time-sensitive. The most common cause of cardiac arrest in adults is an abnormal heart rhythm that an AED can correct, but the chance of success decreases rapidly with every minute. This is why getting an AED on the person’s chest while continuing CPR gives them the best possible chance.
Common Fears That Delay Action
Many bystanders hesitate because they’re afraid of doing something wrong. Cracking a rib during CPR is a real possibility, especially in older adults, but broken ribs heal. A brain starved of oxygen for several minutes does not. Imperfect CPR is dramatically better than no CPR.
Others worry about legal consequences. Every U.S. state has some form of Good Samaritan law that protects bystanders who voluntarily provide emergency care. These laws shield you from civil liability for ordinary mistakes, like the rib example. They don’t cover reckless or intentionally harmful behavior, but good-faith efforts to save someone’s life are protected. You won’t face a lawsuit for trying to help.
If the person is gasping, you might assume they’re still breathing and don’t need help. Those gasps typically stop within about four minutes. They’re actually a sign that the brain is still active enough to trigger a reflex, which means there’s still time to save them, but only if you act now.
What Happens When Paramedics Arrive
Keep doing compressions until emergency medical services physically take over. Paramedics will bring advanced equipment and medications that build on the CPR and defibrillation you’ve already provided. The survival chain depends on each link: your recognition of the emergency, your call to 911, your chest compressions, and the AED all buy time for the advanced care that follows. Without those first links, the later ones can’t compensate.