Agonal breathing is an abnormal, involuntary respiratory pattern signaling a severe, life-threatening medical emergency. This distinctive pattern is not effective breathing, despite the appearance of gasping or struggling for air. It manifests as a reflex when the body is in profound distress, most commonly associated with sudden cardiac arrest. Recognizing this labored breathing indicates a failure of the body’s circulatory system and demands immediate action.
Identifying Agonal Breathing
The visual and auditory characteristics of agonal breathing are specific and do not resemble normal respiration or heavy breathing. A person exhibiting this pattern presents with sudden, sporadic gasps that appear labored and involuntary. These gasps are typically shallow half-breaths, where the chest barely rises or falls.
The sound is often described as a loud snort, a gurgle, or a strained moan. Witnesses frequently liken the sound to a fish out of water, accompanied by an open-mouthed, reflexive jaw movement. This auditory sign results from the ineffective effort to pull air into the lungs.
The rhythm is markedly irregular and infrequent. Gasps may occur only a few times a minute, sometimes as slow as two or three times every 60 seconds. Long pauses, potentially lasting 15 to 30 seconds, may occur between these isolated efforts.
A person experiencing agonal breathing is typically unresponsive or quickly losing consciousness. This lack of awareness distinguishes it from other labored breathing, such as the “death rattle” caused by throat secretions. Since the gasps are insufficient to deliver adequate oxygen, mistaking these movements for effective breathing is a fatal error.
The Underlying Physiological Cause
Agonal breathing represents a primitive, reflexive response triggered by severe oxygen deprivation (hypoxia) within the brain. When the heart stops pumping blood effectively, the brain is starved of oxygen. The higher centers of the brain quickly begin to fail without this constant supply of oxygenated blood.
The lower part of the brainstem, which controls basic survival functions like breathing, is more resilient to oxygen loss. As the higher centers become unresponsive, the respiratory centers in the brainstem initiate a final neurological signal. This signal attempts to stimulate the diaphragm and chest muscles to take a breath.
The result is the characteristic, involuntary gasping movement, which is a reflex rather than true, coordinated respiration. This reflex is often preserved for a few minutes after the heart has ceased effective circulation, occurring in approximately 40% of out-of-hospital cardiac arrest cases.
This mechanism explains why the breaths are irregular and shallow; they are a sporadic, reflexive spasm, not a controlled breathing cycle. While cardiac arrest is the most frequent cause, this pattern can also be triggered by other events leading to acute brain hypoxia, such as severe stroke, drowning, or opioid overdose. The underlying cause is always an interruption of oxygen delivery to the brain tissue.
Urgent Steps to Take
Witnessing agonal breathing demands immediate, decisive action, as it signifies a time-sensitive medical emergency. The first step is to immediately call emergency medical services (911 or 999). When speaking to the dispatcher, state that the person is unresponsive and exhibiting abnormal, gasping, or irregular breathing.
Agonal breathing is a strong indicator of cardiac arrest, so bystanders should begin chest compressions immediately if the person is unconscious. Do not delay intervention by waiting for breathing to improve or searching for a pulse; agonal breathing confirms the need for immediate circulatory support.
Hands-only cardiopulmonary resuscitation (CPR) should be started right away, pressing hard and fast in the center of the chest at a rate of 100 to 120 times per minute. This speed is necessary to manually circulate blood and oxygen. Continue compressions without interruption until emergency responders arrive.
If an Automated External Defibrillator (AED) is available, retrieve and apply it quickly. The device’s voice prompts guide the user through delivering a life-saving electrical shock. The combination of emergency calls, continuous chest compressions, and rapid AED use offers the best chance of survival.