Out-of-hospital cardiac arrest (OHCA) is a leading cause of death among adults in the Western Countries. OHCA affects approximately 400,000 individuals in Europe annually (2). Because of the heterogeneity of geographical and logistical aspects, a patient’s characteristics, as well as medical and community reporting, there are substantial differences among countries. In any case, the global average incidence is about 55 adult OHCA of presumed cardiac cause per 100.000 person-years (2).
Cardiopulmonary resuscitation (CPR) is a first aid manoeuvre which, if used correctly and early, can save lives in the event of a cardiac arrest. CPR in adults involves the execution of two specific manoeuvres: cardiac massage (chest compressions) and artificial ventilation (mouth-to-mouth respiration or mouth-to-mask respiration – recommended).
In the first few minutes following OHCA, swift implementation by bystanders of a limited number of critical actions, known as “chain of survival”, can, regardless of the underlying cause, substantially increase the chance of survival (3). The actions needed to be taken by the so called “first responders” include: 1) rapid activation of the Emergency Medical Service by calling a dedicated phone number; 2) rapid initiation of CPR; 3) prompt application and use of an automated external defibrillator (AED) (4).
An AED is a device that analyses the heart rhythm and evaluates whether it is shockable, warns the rescuer if defibrillation is needed, and delivers a shock if it is necessary. Two electrodes are placed on the patient’s chest and connected to the equipment. An algorithm inside the device analyses the heart rhythm and determines whether a shock is needed or not to save the patient. Out of all OHCA, about a quarter (27%) have a presenting rhythm that can be treated by an external defibrillator (2).
The reported average survival following OHCA in an adult population is poor, about 7% (ranging from 2% to 11%), but significant efforts are being invested in improving it (5, 6). The reason for the wide variability of the survival rate is not completely understood and the determinants of outcome need to be fully elucidated. The factors believed to influence outcome do not only depend on the different National Health Organizations or the time of arrival of the Emergency Medical Services. Factors related to “first responders”, as time from recognition of cardiac arrest to bystander CPR, quality of CPR itself, and availability or awareness of presence of AEDs in public spaces surely play relevant roles (6).
In fact, several national initiatives have been undertaken to increase awareness in lay people of fast recognition and management of OHCA to facilitate participation in the pre-hospital “chain of survival”. All these initiatives have been demonstrated to significantly improve the outcome of victims (7).