Background -Despite recent advances, the average survival after out-of-hospital cardiac arrest (OHCA) remains below 10%. Early defibrillation by an automated external defibrillator (AED) is the most important intervention for OHCA patients, showing survival proportions above 50%. Accordingly, placement of AEDs in the community as part of a public access defibrillation program (PAD) is recommended by international guidelines. However, different strategies have been proposed on how exactly to increase and make use of public available AEDs. This systematic review aimed to evaluate the effect of PAD and the different PAD strategies on survival after OHCA. Methods -Pubmed, Embase, and the Cochrane Library were systematically searched on August 31, 2015 for observational studies reporting survival to hospital discharge in OHCA patients where an AED had been used by non-emergency medical services.
PAD was divided into three groups according to who applied the defibrillator: non-dispatched lay first responders, professional first responders (firefighters/police) dispatched by the Emergency Medical Dispatch Center (EMDC) or lay first responders dispatched by the EMDC. Results -A total of 41 studies were included; 18 reported PAD by non-dispatched lay first responders, 20 reported PAD by EMDC-dispatched professional first responders (firefighters/police) and three reported both. We identified no qualified studies reporting survival after PAD by EMDC-dispatched lay first responders. The overall survival to hospital discharge after OHCA treated with PAD showed a median of 40.0% (range 9.1-83.3). Defibrillation by non-dispatched lay first responders was associated with the highest survival with a median of 53.0% (range 26.0-72.0) while defibrillation by EMDC-dispatched professional first responders (firefighters/police) was associated with a median survival of 28.6% (range 9.0-76.0).
A meta-analysis of the different survival outcomes could not be performed due to the large heterogeneity of the included studies. Conclusions -This systematic review showed a median overall survival of 40% for OHCA patients treated by PAD. Defibrillation by non-dispatched lay first responders was found to correlate with the highest impact on survival compared to EMDC-dispatched professional first responders.
PAD by EMDC-dispatched lay first responders could be a promising strategy, but evidence is lacking.