What device is associated with the third step in the survival chain?

The third step in the survival chain typically concerns advanced interventions for cardiac arrest and other critical conditions where immediate medical assistance is needed. The Automated External Defibrillator (AED) or defibrillator is a crucial device used to restore normal heart rhythm in individuals experiencing sudden cardiac arrest.

When a person suffers from cardiac arrest, the survival chain emphasizes recognizing the emergency, activating emergency response, and providing early defibrillation to increase the chances of survival. The AED is designed to analyze the heart's rhythm and deliver an electrical shock if necessary, making it an essential tool in this context. By using an AED promptly, the chances of survival significantly increase compared to waiting for advanced medical personnel to arrive.

In contrast, the other options—stethoscope, oxygen mask, and ventilator—have roles in either assessment or supportive care but are not specifically aimed at the immediate restoration of normal heart rhythm, which is the focus of the third step in the survival chain.