What is the first step in the chain of survival?

The first step in the chain of survival is the activation of CPR. This initial step is crucial because it ensures that emergency medical services (EMS) are alerted as soon as a cardiac arrest is suspected. Activating CPR allows responders to arrive promptly, providing a better chance of survival for the patient.

After activation, subsequent steps such as performing chest compressions, defibrillation, and advanced life support naturally follow. Each of these steps builds on the response initiated by activating CPR, but without that crucial first action to alert help, the other steps cannot be effectively implemented in a timely manner. Activation is therefore the foundational step that sets the entire rescue process in motion, making it the correct answer in the context of the chain of survival.