[Identification of common locations of out-of-hospital cardiac arrests in a German metropolis].

Background: Most patients who suffer a sudden cardiac arrest initially have a shockable rhythm. Fast defibrillation and correctly performed cardiopulmonary resuscitation (CPR) are key factors for patient survival. These can be carried out by bystanders if an automated external defibrillator (AED) is available even in the absence of emergency services.

Aim: The place and time of CPRs in a German city were investigated and the strategic placement of emergency medical services and AEDs necessary were evaluated.

Methods: All prehospital resuscitation attempts by Bochum's emergency services in 2011 were retrospectively analyzed. The city was divided into a grid, according to the city map to describe the location of every resuscitation. The distribution of cases was correlated to the city grid and time of day.

Results: There were 299 cardiac arrests (mean age 74.2 ± 12.47 years; 59% of patients were male). Most resuscitations happened in a home environment between 8 am and 8 pm. There was a higher proportion of resuscitation attempts in grid squares with a high population density. Of the resuscitations in public places 16 of 47 (34%) happened in city district centers. In 72% of all cases, only a nonshockable rhythm could be documented as primary arrhythmia on the arrival of the emergency services. Of the 299 attempted resuscitations, a return of spontaneous circulation was achieved in 41%.

Conclusions: The knowledge about increased frequency of resuscitations in city centers provides insight for strategic placement of emergency devices and services in those areas. This can possibly minimize the time until first response and enables early defibrillation with AED in a first-responder program. In addition, bystanders should obtain clear instructions for resuscitation by the dispatcher of the emergency services.