The preferred method of CPR, when possible, is conventional CPR that combines chest compressions with rescue breaths at a ratio of 30 compressions to 2 breaths. This approach delivers both circulation and oxygen, giving the person the best chance of survival. However, if you are untrained or unwilling to give rescue breaths, hands-only CPR (chest compressions without breaths) is still highly effective for adults and far better than doing nothing.
Why Compressions With Breaths Is Preferred
Chest compressions keep blood moving through the body, but that blood gradually loses its oxygen content. Rescue breaths replenish the oxygen supply, which is critical for protecting the brain and vital organs. The 30:2 ratio, recommended by the American Heart Association since 2005, was specifically designed to maximize blood flow by keeping pauses for breaths as short as possible while still delivering enough air.
For trained rescuers, the combination of compressions and ventilations remains the gold standard. This is especially true when the cardiac arrest has gone on for more than a few minutes, because the body’s residual oxygen has been used up and compressions alone can only circulate oxygen-depleted blood.
When Hands-Only CPR Is the Right Choice
Hands-only CPR is the recommended approach for bystanders who are not trained in CPR. The American Heart Association classifies this as a strong recommendation for witnessed adult cardiac arrest, meaning you saw the person suddenly collapse. The instructions are simple: call 911, then push hard and fast in the center of the chest at a rate of 100 to 120 compressions per minute. Minimize any interruptions.
The reasoning is practical. Many bystanders hesitate to perform CPR because they’re uncomfortable with mouth-to-mouth breathing or unsure of the technique. Hands-only CPR removes that barrier. In the first several minutes of a sudden cardiac arrest, the blood still contains enough oxygen that continuous compressions can keep it circulating effectively. Studies in both animals and humans have shown that compression-only CPR produces similar or even better outcomes compared to conventional CPR for adults with witnessed sudden collapse, largely because rescuers spend more time compressing and less time pausing.
This recommendation has an important boundary, though. Hands-only CPR applies to adults who suddenly collapse from a likely cardiac cause. It does not apply to children, unwitnessed arrests, or situations where the arrest stems from a breathing problem like drowning or drug overdose.
Situations That Require Rescue Breaths
Some emergencies cause the heart to stop because the person stopped breathing first. In these cases, the body’s oxygen reserves are already depleted by the time cardiac arrest occurs, and compressions alone won’t deliver what the tissues need. Rescue breaths become essential in these scenarios:
- Drowning: The lungs may be filled with water, and oxygen levels are critically low before the heart stops.
- Opioid overdose: Opioids suppress the body’s automatic drive to breathe. Oxygen levels drop, carbon dioxide builds up, and without ventilation, the result is organ failure. Rescue breathing is physiologically matched to this type of emergency, and for someone who still has a pulse, rescue breaths alone may be more beneficial than full CPR.
- Choking or suffocation: The underlying problem is a lack of air, so restoring airflow is a priority.
For all of these, trained rescuers should provide conventional CPR with both compressions and breaths.
CPR for Infants and Children
Pediatric cardiac arrest is different from adult cardiac arrest. In children, the heart usually stops because of a breathing problem rather than a sudden electrical malfunction. This makes rescue breaths especially important. Large studies of children who experienced out-of-hospital cardiac arrest have consistently shown better survival when bystanders provided compressions with breaths compared to compressions alone.
The numbers tell a clear story. One-month survival for children receiving hands-only CPR was 12.3%, compared to 18.0% for those who received conventional CPR with breaths. The gap widened further when looking at neurological outcomes: 6.3% of children receiving hands-only CPR had favorable brain recovery, versus 9.0% with conventional CPR. Lay rescuers are encouraged to provide breaths for infants and children if they are able and willing, using either a 30:2 or 15:2 compression-to-ventilation ratio.
For infants, compressions should be performed using either a one-hand technique or the two-thumb encircling hands method, where you wrap both hands around the infant’s torso and compress the breastbone with your thumbs. The older two-finger technique has been dropped from guidelines because it doesn’t generate enough depth. For children ages one to eight, using two hands for compressions produces deeper, more effective compressions than one hand.
What Makes CPR High Quality
Regardless of which method you use, the quality of your compressions determines whether CPR actually works. Poor technique can render even the “preferred” method ineffective. The key targets for adults are:
- Compression depth: At least 2 inches (5 centimeters). For infants and children, compress at least one-third the depth of the chest.
- Compression rate: 100 to 120 per minute. Think of the beat of “Stayin’ Alive” by the Bee Gees.
- Full chest recoil: Let the chest come all the way back up between compressions. This creates a slight vacuum inside the chest that pulls blood back into the heart, reloading it for the next compression. Even trained rescuers struggle with this, so it takes conscious effort.
- Minimal interruptions: The goal is a chest compression fraction of at least 60%, meaning compressions should be happening for at least 60% of the total resuscitation time. Every pause lets blood pressure drop, reducing the chance of survival.
Pushing hard enough is one of the most common failure points. Two inches of depth requires significant force, and many rescuers don’t compress deeply enough, especially as fatigue sets in. If multiple people are present, switching off every two minutes helps maintain compression quality.
Choosing the Right Method
The decision tree is straightforward. If you are trained in CPR and confident in your skills, provide conventional CPR with 30 compressions followed by 2 breaths for adults. This is the preferred method. If the victim is an infant or child, rescue breaths are particularly important and should be included whenever possible. If someone collapsed due to drowning, overdose, or choking, prioritize getting air into their lungs alongside compressions.
If you are untrained, uncomfortable with rescue breaths, or unsure what caused the collapse in an adult, hands-only CPR is effective and recommended. The single most important thing is to start compressions immediately and keep going until emergency medical services arrive. A person receiving imperfect CPR has a dramatically better chance than a person receiving none at all.