The breathing pattern characterized by irregular gasping breaths is called agonal breathing (also known as agonal respiration). It consists of slow, labored gasps that are spaced irregularly and are not effective at moving air into the lungs. Agonal breathing is a brainstem reflex, often described as the last respiratory pattern before breathing stops entirely, and it signals a medical emergency, most commonly cardiac arrest.
What Agonal Breathing Looks and Sounds Like
Agonal breaths don’t look like normal breathing. Instead of the steady rise and fall of the chest you’d expect, you’ll see infrequent, labored gasps that may involve the jaw, neck, or upper body. The person is unresponsive between gasps, and the breaths may be separated by long pauses of several seconds or more.
People who witness agonal breathing describe it in many different ways: snoring, gurgling, moaning, snorting, or labored breathing. There’s no single sound it makes. Some gasps are nearly silent, while others produce a grunting or groaning noise. The breaths typically slow down over time and, without intervention, stop within about four minutes of onset, though the duration can range from just one or two breaths to a prolonged period lasting minutes or even hours.
Why It Happens
Agonal breathing originates in the lower brainstem, which contains the most primitive breathing centers in the brain. When the higher brain loses oxygen (most often because the heart has stopped pumping blood), these deep brainstem neurons continue firing on their own for a short time, producing reflexive gasps. It is not conscious breathing. The person is not aware and is not getting meaningful oxygen from these gasps.
The most common cause is cardiac arrest. In a study of 445 out-of-hospital cardiac arrests in King County, Washington, 40% of victims displayed agonal breathing. It was even more common in witnessed arrests (55%) and in cases where the heart was in ventricular fibrillation, a rhythm that responds well to defibrillation (56%).
Why Bystanders Mistake It for Normal Breathing
This is the most dangerous misconception about agonal breathing. Because the person appears to be making some effort to breathe, bystanders often assume they are alive and breathing on their own, and they delay or skip CPR. The 2025 American Heart Association guidelines specifically flag this problem: the presence of agonal breathing is one of the most common reasons bystanders misdiagnose someone as not being in cardiac arrest.
The numbers bear this out. In one study, when a person in cardiac arrest had no breathing at all, 83% of bystanders started CPR. But when agonal breathing was present, only 54% started CPR. That hesitation costs lives.
What You Should Do
If someone collapses, is unresponsive, and is only gasping irregularly, treat it as cardiac arrest. Call emergency services immediately, then start chest compressions. Do not wait to see if breathing improves. The AHA guidelines are clear: the benefit of giving CPR to someone in cardiac arrest far outweighs any risk of giving compressions to someone who doesn’t need them.
Agonal breathing actually creates a small amount of negative pressure in the chest, which pulls some blood back toward the heart. When combined with chest compressions, this can help maintain circulation to the brain. That’s one reason why people who gasp during cardiac arrest have significantly better outcomes. In a large study published in Circulation, 28% of cardiac arrest patients who gasped survived to hospital discharge, compared to only 8% of those who did not gasp. Among those who received bystander CPR, the gap was even wider: 39% survival in gaspers versus 9% in non-gaspers.
Agonal Breathing vs. Other Abnormal Patterns
Several other breathing patterns involve irregular rhythms but have different causes and appearances. Knowing the differences can help you understand what you’re seeing.
- Cheyne-Stokes breathing follows a predictable cycle: breaths gradually get deeper, then shallower, then pause completely before the cycle repeats. It’s most associated with heart failure and occurs in patients who are conscious or semi-conscious, not in sudden collapse.
- Biot respiration involves clusters of normal-depth breaths separated by complete pauses. It results from damage to a specific area of the brainstem called the pons, often from stroke, trauma, or opioid overdose.
- Apneustic breathing features prolonged, gasping inhales followed by very short exhales. Like Biot breathing, it points to brainstem injury and carries a poor prognosis.
The key distinction is context. Agonal breathing happens in someone who has suddenly become unresponsive, typically from cardiac arrest. The other patterns tend to occur in people who are already hospitalized or have known neurological conditions. If you encounter someone who has collapsed and is making irregular gasping sounds, agonal breathing is the most likely explanation, and it demands immediate action.
What Agonal Breathing Tells Medical Teams
For emergency responders, the presence of agonal breathing is actually an encouraging sign. It indicates that the brainstem still has some activity, which suggests the brain hasn’t been without oxygen for too long. Agonal gasps serve as a natural indicator of preserved neurological function. Patients who continue gasping during CPR tend to have better brain outcomes than those who stop.
This is why speed matters so much. Agonal breathing is most frequent in the first moments after cardiac arrest and fades quickly. Every minute without CPR is a minute closer to the gasping stopping entirely, and with it, the window for a good neurological recovery.