Which signs may indicate that a person is in cardiac arrest?

The indication that someone is in cardiac arrest primarily revolves around their breathing status. When a person is in cardiac arrest, they will not be breathing at all, or if there is any breathing, it may manifest as gasping, which is also referred to as agonal breathing. This state implies that the heart is no longer circulating blood adequately, leading to a cessation of normal breathing.

While fainting, pale skin, and chest pain can be associated with various heart conditions and may occur before a cardiac arrest, they are not definitive signs of a person being in cardiac arrest. Fainting might suggest a temporary reduction in blood flow or a syncopal episode rather than a complete cessation of heart function. Pale skin can indicate poor circulation or shock but does not confirm cardiac arrest, and chest pain is often a symptom of a heart issue but not a direct indication that cardiac arrest has occurred. Thus, the absence of normal breathing or the presence of gasping is the most reliable sign that signals a person is in cardiac arrest, warranting immediate life-saving intervention such as CPR and the use of an AED if available.