The location and incidence of out-of-hospital cardiac arrest in Georgia: implications for placement of automated external defibrillators.

Objective: Prior studies of automated external defrillator placement strategies for public access defibrillation (PAD) have addressed only the venue of out-of-hospital cardiac arrest (OOHCA) in large urban areas. This study evaluates the relationship between population density and the incidence and location of OOHCA.

Methods: This study was a retrospective analysis of 624,199 Georgia state emergency medical services patient care reports (PCRs) in 2000. The PCR categorized these cardiac arrests by county into 12 location options. Counties were divided into population densities of <100, 100-400, 400-1,000, and >1,000 persons per square mile. The incidence of cardiac arrest for each location type was calculated for each population density group.

Results: The <100 density group had only 21.77% of the state's population but 30.96% of the state's cardiac arrests, whereas the >1,000 density group had 35.46% of the population but only 23.55% of the cardiac arrests (p<0.0001). The relative risk (95% confidence interval) for OOHCA in the <100 density group compared with the >1,000 density group was 2.14 (2.00, 2.29). The percentage of OOHCAs that occurred in the home for each population density group was: <100 persons per square mile, (67.67%); 100-400 persons per square mile, (68.83%); 400-1,000 persons per square mile, (65.75%); and >1,000 persons per square mile (62.09%) (p=0.0001).

Conclusions: There are variations in incidence and location of OOHCA based on population density in Georgia. As population density increases, the incidence percentage of OOHCAs decreases. However, as population density increases, there is an increase in the percentage of cardiac arrests occurring outside the home, where more OOHCAs could potentially benefit from PAD.