To whom should you apply an AED?

An Automated External Defibrillator (AED) is designed specifically for use in situations where a patient is in cardiac arrest, which is characterized by the absence of respirations and a pulse. This is critical because the primary function of the AED is to analyze the heart's rhythm and deliver a shock if necessary to restore a normal heartbeat. Applying an AED to a patient who is not breathing and does not have a pulse maximizes the chances of survival through rapid defibrillation in cases of life-threatening arrhythmias.

In contrast, while chest discomfort, significant traumatic injuries, and low blood pressure might indicate serious medical conditions, these situations do not warrant the use of an AED unless the patient is in cardiac arrest. Each of these scenarios requires a different medical response and assessment, and using an AED on patients in these conditions may not only be inappropriate but could also delay necessary treatment. Therefore, applying an AED should be reserved strictly for adult patients who are confirmed to be without respirations or a pulse.