Final answer:
In a cardiac emergency, one should call 911 and retrieve an AED immediately. AEDs help diagnose the heart's rhythm and deliver a necessary shock, while CPR supports blood flow until such measures can be taken.
Step-by-step explanation:
Calling 911 is crucial in a cardiac emergency when someone is unresponsive and not breathing or only gasping. Similarly, one should retrieve an Automated External Defibrillator (AED) as soon as possible. AEDs are portable devices commonly located in public areas, designed to be used by the layperson. An AED diagnoses the heart rhythm and, if necessary, delivers a shock to help the heart resume a normal rhythm. Performing CPR prior to the use of an AED can be important as it maintains blood flow to the brain and other vital organs, potentially increasing the chance of survival until the AED is in use or emergency responders arrive.