In what situation is the use of an AED mandatory for EMTs under NCOEMS standards?

The use of an AED is mandatory for EMTs in situations where a patient is unresponsive and not breathing. This condition is typically indicative of a possible cardiac arrest, where immediate defibrillation can significantly increase the chances of survival. When a patient is unresponsive and does not have effective ventilation, it suggests the heart may not be pumping effectively, leading to a lack of oxygenated blood being circulated to the vital organs. Prompt action with an AED can help to restore a normal heart rhythm, which is crucial for the patient's chance of recovery.

The other situations mentioned either do not specifically indicate a cardiac arrest or do not necessitate immediate AED use. Severe bleeding, chest pain, and known heart conditions may require medical attention but do not automatically trigger the same urgency for defibrillation and the use of an AED as when a patient is unresponsive and not breathing. Therefore, the distinction lies in the immediacy and critical nature of cardiac arrest as the correct scenario for AED utilization by EMTs.