In a witnessed cardiac arrest scenario, what should you do if you are alone and there is no mobile phone available?

In a witnessed cardiac arrest scenario where you are alone and do not have access to a mobile phone, leaving to activate the emergency response system and retrieving an AED before initiating CPR is the best course of action to maximize the patient's chances of survival. While beginning CPR immediately is critical in many situations, the need for rapid intervention with an AED—especially if the collapse was witnessed—warrants an immediate call for help and access to this life-saving device.

By leaving to activate the emergency response system, you ensure that trained professionals are on the way while also coordinating the use of an AED. This step is crucial because early defibrillation, when indicated, significantly improves the chances of survival in cases of shockable rhythms. Initiating CPR without calling for help first may delay the arrival of advanced care and life-saving interventions, which is particularly important in a witnessed event where every second counts.

In this context, CPR is vital, but acquiring additional resources like an AED or professional help is essential in ensuring the overall effectiveness of the resuscitation efforts.