Agonal breathing, or agonal respiration, is the medical term for the gasping that people do when they’re struggling to breathe because of cardiac arrest or another serious medical emergency.

The desperate gasping for air is usually a symptom of the heart no longer circulating oxygenated blood, or there’s an interruption of lung activity that’s reducing oxygen intake. It can often signal that death is imminent.

If you see someone struggling to breathe, call your local emergency medical services immediately.

Agonal breathing isn’t the same as a “death rattle.” This is the gurgling noise that some people make when they’re dying. Death rattle is caused by saliva or mucus collecting in the throat or chest. Agonal breathing is instead an abnormal and often brief and inadequate pattern of breathing.

Agonal breathing may sound like gasping, but it can also sound like snorting and labored breathing. It may even seem as though the person is moaning. The abnormal breathing may last only a few breaths or could go on for hours. The cause of agonal breathing will affect how long it goes on and whether there are other symptoms.

Agonal breathing commonly occurs with cardiac arrest or a stroke. It’s possible the person may lose consciousness while gasping. Stroke symptoms include:

  • weakness on one side of the body
  • facial droop
  • lack of coordination
  • poor speech or an inability to understand speech
  • a sudden headache

Agonal breathing can occur when someone has gone into cardiac arrest. Unlike a heart attack — which happens when one or more arteries narrow and stop blood from reaching the heart muscle — cardiac arrest is an electrical problem. During cardiac arrest, the heart stops beating effectively. This is known as an arrhythmia, or pattern of irregular heartbeats.

Blood continues to flow briefly in the brain and other organs, which can cause gasps for a few minutes after the heart stops. If cardiac arrest is the cause of agonal breathing, the labored breaths may only last a few minutes. Having had a heart attack makes it more likely to have cardiac arrest.

Another common cause of agonal breathing is cerebral ischemia, or a reduction in blood flow to the brain. This can be caused by a ministroke due to a blood flow blockage within a brain blood vessel. It can also be caused by a hemorrhagic stroke due to a bleeding blood vessel within the brain. Either can lead to a condition called cerebral hypoxia, which is insufficient oxygen supply to the brain regardless of the cause. The brain can have permanent damage if it’s deprived of oxygen for too long.

Gasping for breath is a sign that something is wrong. Anyone gasping for breath — even if there are no other obvious symptoms — needs emergency medical help.

Call your local emergency services and tell the dispatcher about the person’s abnormal breathing and any other symptoms you’ve noticed. If the dispatcher asks if the person is breathing, don’t simply say yes because you hear gasping and snorting. Make it clear that the breathing isn’t steady.

If you’re not sure why the person is having trouble breathing, ask the dispatcher what you should do and if it’s OK to try CPR.

Agonal breathing and CPR

If you believe that someone is in cardiac arrest and is in the middle of an agonal breathing episode and you know CPR, you should begin chest compressions and do what you can to continue chest compressions until help arrives.

A person in cardiac arrest may also be revived with the help of an automated external defibrillator (AED). There’s no need to perform mouth-to-mouth. This has been shown to interfere with blood flow to the heart muscle.

If cardiac arrest occurs, the person usually drops or slumps to the ground.

Regardless of the cause of agonal breathing, the first response of paramedics or emergency room personnel is to restore a normal heart rhythm and breathing.

If the heart has stopped, a defibrillator may be needed to restart it. Mechanical ventilation may also be necessary to get air into the lungs and restart oxygen flow through the body. Blood pressure may also need to be maintained with medications.

Agonal breathing is often fatal. Brain cells can die if they’re deprived of oxygen for more than five minutes.

If you know how to respond to someone having this breathing difficulty, you may be able to save their life. The most important response is to contact local emergency services. Paramedics may be able to preserve heart and brain health, as well as the health of other organs if they can reach the person in time.

A personal or family history of heart attack, history of heart failure, or an abnormal heart rhythm increases a person’s risk for cardiac arrest. High blood pressure and a family history of strokes make you more vulnerable to stroke.

If you know someone who’s at risk for a stroke or cardiac arrest, know the symptoms of agonal breathing. You should also know how to respond:

  • Always call your local emergency services first. Most ambulances are equipped with the tools, medications, and communication equipment necessary to help keep the person alive.
  • If you’re trained in CPR, provide continuous chest compressions until help arrives.

Agonal breathing is a sign that something is wrong. It should never be ignored.