Rescue breaths are indicated whenever a person has stopped breathing or is breathing inadequately, whether their heart is still beating or not. The two broadest categories are respiratory arrest (the person has a pulse but isn’t breathing) and cardiac arrest (no pulse, no breathing). Within those categories, certain situations make rescue breaths especially critical: drowning, opioid overdose, choking, and any cardiac arrest in an infant or child.
Respiratory Arrest: A Pulse but No Breathing
The clearest indication for rescue breaths is when someone has a pulse but has stopped breathing or is only gasping. This is respiratory arrest, and ventilation is the single most important intervention. Without oxygen delivery, high-demand organs like the heart and brain can sustain irreversible damage within minutes. The goal is straightforward: breathe for the person until they start breathing on their own or emergency medical services arrive.
Common causes of respiratory arrest include opioid overdose, severe allergic reactions, near-drowning, and airway obstruction. In each of these, the heart may still be pumping, but the lungs have stopped doing their job. Rescue breaths restore oxygen flow and clear carbon dioxide buildup.
Cardiac Arrest in Adults
When an adult’s heart stops, chest compressions are the top priority because they keep blood circulating. For bystanders who haven’t been trained in CPR or who feel uncomfortable giving mouth-to-mouth, hands-only CPR (compressions without breaths) is a reasonable option and far better than doing nothing. But the 2025 American Heart Association guidelines encourage trained rescuers to add rescue breaths to compressions because the combination may improve outcomes compared with compressions alone.
The standard ratio is 30 chest compressions followed by 2 rescue breaths, and this stays the same whether one person or two people are performing CPR. Each breath should be delivered over about one second, just enough to make the chest visibly rise. Blowing too hard or too fast pushes air into the stomach rather than the lungs, which creates its own problems.
Why Children and Infants Need Breaths
Rescue breaths are far more important in pediatric emergencies than in adult ones. Unlike adults, whose cardiac arrests usually stem from a heart rhythm problem, children and infants typically go into cardiac arrest because of a breathing problem first. Their lungs fail, oxygen drops, and then the heart stops. That chain of events means restoring oxygen through rescue breaths addresses the root cause, not just a symptom.
Research from Children’s Hospital of Philadelphia found that across all pediatric age groups, CPR with rescue breaths produced better neurological outcomes than compression-only CPR. The finding was starkest in infants: compression-only CPR performed no better than no bystander CPR at all. Rescue breathing was the only effective strategy for that age group. For children, the compression-to-breath ratio is 30:2 with a single rescuer and drops to 15:2 when two rescuers are present, allowing more frequent breaths.
Drowning and Suffocation
Drowning is one of the strongest indications for immediate rescue breaths. Because the person’s lungs have been deprived of oxygen (often filled with water), the fundamental problem is a lack of air, not a lack of circulation. Cerebral hypoxia is the principal driver of brain damage and death in drowning victims, so airway management and breathing take precedence over chest compressions.
Current guidelines recommend starting with 5 initial rescue breaths before beginning chest compressions in a drowning victim. This contrasts with the standard 2 breaths used in typical CPR and reflects how urgently the lungs need to be re-oxygenated. The same principle applies to suffocation and strangulation: when the cause of the emergency is loss of airflow, rescue breaths are the priority intervention.
Opioid Overdose
An opioid overdose suppresses the brain’s drive to breathe. The person’s heart often continues beating, but respiratory rate drops dangerously low or stops entirely. This makes it a textbook indication for rescue breaths. The recommended response is to open the airway, reposition the head, and begin rescue breathing while also administering naloxone if available. Rescue breaths buy time for the naloxone to reverse the opioid’s effect on the brain. Without ventilation, the person can progress from respiratory arrest into full cardiac arrest.
What Exhaled Air Actually Delivers
A reasonable question is whether exhaled air contains enough oxygen to help. Room air is about 21% oxygen. The air you breathe out during rescue breathing contains roughly 16 to 17% oxygen. That’s lower, but it’s more than sufficient to sustain life. Your body only extracts a fraction of the oxygen in each breath, so the remainder passes to the other person’s lungs and into their bloodstream. It is not ideal compared with supplemental oxygen from a tank, but in an emergency it is effective and immediately available.
Risks of Incorrect Technique
The main complication of rescue breathing is gastric inflation, where air enters the stomach instead of the lungs. This happens when breaths are delivered too forcefully or too quickly. Research using predictive models found that breaths shorter than one second required mouth pressures high enough to force air past the valve between the esophagus and stomach. That air in the stomach can trigger vomiting, which then risks aspiration into the lungs.
To avoid this, each rescue breath should last about one second and deliver just enough volume to produce a visible chest rise. Blowing harder does not help. If the chest doesn’t rise, the most likely problem is head positioning: tilting the head back and lifting the chin usually opens the airway enough for air to reach the lungs. Overventilation also raises pressure inside the chest, which can reduce blood flow back to the heart during CPR, undermining the very circulation that compressions are trying to maintain.
Summary of Key Indications
- Respiratory arrest with a pulse: the single clearest indication, regardless of cause
- Cardiac arrest in trained rescuers: 30 compressions to 2 breaths improves outcomes over compressions alone
- All pediatric cardiac arrests: breaths are essential because the arrest is almost always caused by a breathing problem
- Drowning or suffocation: breathing takes priority over compressions, with 5 initial breaths recommended for drowning
- Opioid overdose: rescue breaths sustain the person while naloxone reverses the drug’s respiratory suppression