For adults, call 911 immediately, before starting chest compressions. For children and drowning victims, the guidance is different: perform about 2 minutes of CPR first, then call. In both cases, every minute of delay in getting paramedics on the way reduces the chance of survival to hospital discharge by roughly 6%.
The exact sequence depends on the victim’s age, the likely cause of the arrest, and whether you’re alone or have someone nearby who can make the call for you.
Adults: Call First, Then Start CPR
The 2025 American Heart Association guidelines are clear: when you find an adult in cardiac arrest, a lone rescuer should activate the emergency response system first and then immediately begin CPR. The reasoning is straightforward. Adults who collapse suddenly are most likely in a heart rhythm called ventricular fibrillation, which needs a defibrillator to correct. Getting paramedics and their equipment on the way as fast as possible gives the person the best shot.
If someone else is nearby, tell them to call 911 while you begin chest compressions right away. Two rescuers means you don’t have to choose between calling and compressing.
Children and Drowning: CPR First, Then Call
For infants, children, and drowning victims of any age, the priorities flip. A lone rescuer should perform about 2 minutes of CPR (roughly 5 cycles of 30 compressions and 2 breaths) before stepping away to call 911.
The reason comes down to what’s happening inside the body. In children, cardiac arrest is rarely caused by a heart rhythm problem. Only about 3% of cardiac arrests in kids under 8 involve ventricular fibrillation, compared to 42% in adults over 30. Instead, the heart usually stops because the child stopped breathing first, and the body ran out of oxygen. Drowning follows the same pattern: the heart fails because of severe oxygen deprivation. In these cases, getting oxygen circulating through chest compressions and rescue breaths during those first 2 minutes can be more valuable than an immediate call for a defibrillator.
After those 2 minutes, if you’re still alone, call 911 and retrieve an AED if one is nearby.
Use Your Phone’s Speaker Mode
Most people today carry a mobile phone, which changes the math on timing considerably. The AHA now acknowledges that with a hands-free option, a lay rescuer can activate the emergency response system and begin CPR at nearly the same time. Put your phone on speaker, place it on the ground next to the victim, dial 911, and start compressions while speaking with the dispatcher.
This approach eliminates the painful tradeoff between calling and compressing. With the speaker active, you can assess the patient, describe what you see, and receive real-time instructions from the dispatcher without ever pausing chest compressions. Research has highlighted that CPR training materials and dispatcher protocols should incorporate speaker mode more actively, and phone manufacturers should simplify the steps to activate it. In the meantime, it’s worth practicing on your own phone so the steps feel automatic in an emergency.
Recognizing That Someone Needs CPR
Knowing when to call matters less if you don’t recognize cardiac arrest in the first place. The signs seem obvious on paper: someone who is unresponsive and not breathing. In reality, many bystanders are fooled by agonal gasps, which can sound like snoring, gurgling, moaning, or snorting. These irregular, labored sounds are not normal breathing. They’re a sign the brain is still alive but the heart has stopped doing its job.
Bystanders who hear gasping often tell the 911 dispatcher that the person is breathing, which leads the dispatcher to believe it’s not a cardiac arrest. This single misidentification delays everything. If someone is unresponsive and their breathing sounds abnormal, strained, or irregular, treat it as cardiac arrest. Call 911 and begin chest compressions. A person who is gasping actually has a high chance of surviving if compressions start quickly and continue without interruption.
Why Every Minute Counts
A five-year study of out-of-hospital cardiac arrests found that for every 1-minute increase in EMS response time, the likelihood of survival to hospital discharge dropped by 6%. Survival at the scene dropped by the same margin. These numbers compound fast. A 5-minute delay translates to roughly a 26% lower chance of leaving the hospital alive compared to someone who got a faster response.
This is why the call matters so much, and why it should happen as close to the start of CPR as possible. Chest compressions keep blood flowing to the brain and heart, but they can’t restart a stopped heart on their own. The victim needs paramedics, a defibrillator, and medications that only arrive when someone dials 911. The sooner that clock starts, the sooner help arrives.
What to Tell the Dispatcher
When you call 911, the dispatcher needs a few key pieces of information: your location, the fact that someone is unresponsive and not breathing (or only gasping), and roughly how old the victim is. Keep it brief. The dispatcher will guide you from there, including walking you through chest compressions if you haven’t started or aren’t sure of the technique.
You don’t need to diagnose anything or provide a medical history. The dispatcher’s job is to get paramedics moving toward you and keep you performing effective CPR until they arrive.
When to Stop CPR
Once you’ve started compressions, continue without stopping until one of three things happens: an AED arrives and is ready to use, the victim starts moving or clearly begins breathing normally, or EMS personnel arrive and take over. Don’t stop to check for a pulse. Lay rescuers aren’t expected to assess pulse reliably, and pausing compressions interrupts blood flow to the brain. If the person starts moving, coughing, or breathing on their own, you can stop and place them on their side while waiting for paramedics.