Agonal breathing or gasping in someone who is unconscious and unresponsive is a sign that they are in cardiac arrest and need immediate medical help – especially CPR and defibrillation.

Agonal breathing can be mistaken for someone who is moaning or fighting for breath and is still breathing, albeit not normally – this is, in fact, incorrect and the agonal breaths are just the reflex action of the lungs of impulses from the brain.

Agonal breaths occur in approximately 50% of cardiac arrests experienced outside a hospital environment and can last from as little as 2 breaths to many minutes.