What does "witnessed arrest" mean in the context of CPR?

In the context of CPR, "witnessed arrest" refers to a situation where an individual observes the patient suddenly collapse or experience cardiac arrest and is able to initiate the emergency response immediately. This is critical because the immediate recognition of cardiac arrest and prompt initiation of CPR can significantly improve the chances of survival and favorable neurologic outcomes.

When someone witnesses the event, they can react quickly, often leading to a faster initiation of CPR and activation of emergency medical services (EMS). The timeline in such scenarios is crucial; immediate action can lead to better effectiveness in resuscitation efforts, as there is less delay between the onset of cardiac arrest and the beginning of life-saving interventions.

The other options do not accurately capture the essence of "witnessed arrest." The presence of a pre-existing heart condition does not denote witnessing the event. CPR within the first five minutes is beneficial, but witnessing an arrest specifically emphasizes immediate observation and response rather than timing alone. Calling for medical help before collapse does not align with witnessing an arrest; it describes a scenario where the collapse is not directly observed. Witnessing the event ensures a timely response, which is critical in emergency situations.