By observing public AEDs for 5 years, we found that most AEDs had a relatively good state of maintenance, with over 97% of AEDs operating normally. However, 15% of AEDs were not ready for use, and an invalid electrode was the most common cause. In addition, 44% of AEDs were used for less than 24 hours, and accessibility for less than 24 hours was the most frequent cause. Factors related to AED management and maintenance and AED accessibility have improved over time. The proportion of valid electrodes decreased over time. Only about 1% of AEDs have been used. This rate did not change over the study period.

For successful implementation of PADs, four essential elements are required, namely planned and practiced intervention, training of advance rescuers in CPR and the use of an AED, a link to the emergency medical system (EMS) and a continuous quality improvement process.¹¹. In the process of developing and implementing the PAD program, the government or community has paid attention primarily to the installation of AEDs and linkages to the EMS system through legislation or guidelines^12.13. In addition, the AED must be maintained in a ready-to-use state for 24 hours a day. AEDs should be maintained and tested regularly in accordance with applicable rules and regulations established by governmental authorities. However, the maintenance and management of AEDs may be the responsibility of the sites holding the AEDs, as the community or government may not be able to directly manage the maintenance of AEDs. Although every country or community has legal provisions for registering and managing AEDs, many public AEDs are not registered in the national registry system or their management status is often unknown. In the Swedish experience, a large proportion (43%) of AEDs were not registered in their register due to unfamiliarity with the AED register or difficulty in registering despite these AEDs having high functionality.¹⁴. In a report evaluating Canadian public DEA registries, registry governance and administrative processes were found to be flawed. Some registries do not use a standardized process for validation or quality monitoring, which can result in the loss of important AED usage information, including battery and pads validity¹⁵.

In the present study, a qualified inspector checked the management and maintenance status of each AED regarding the manager, accessibility, equipment and condition of the electrodes by visiting the installation site annually. In addition to the on-site inspection, the inspector trained managers and performed corrective actions against barriers to AED accessibility, such as computers, desks, chairs, banners, etc., that were in the way. AED recovery or visibility. Maintenance of the defibrillator itself gradually improved over the observation period, and barriers to AED accessibility decreased over time. In 2015, the South Korean government revised AED management regulations, requiring signage to be posted in locations where AEDs are installed. As the installation of signage for AEDs has become mandatory, the signage installation rate increased from 35.5% in 2015 to 79.7% in 2016 and 91.3% in 2017. AED signage shows the impact of related regulations on AED management. A significant proportion (44%) of AEDs had a duration of use of less than 24 hours and this proportion increased over time. In particular, 3 years after the start of the inspection, the percentage of electrodes that have passed their expiry date has increased. The defibrillator itself does not need a separate function check as it reports data by performing self-tests on its internal circuitry to ensure availability.¹⁶. Two important accessories, namely batteries and electrodes, are subject to inspection during defibrillator maintenance checks, as well as the defibrillator equipment itself. Since the battery is installed in the defibrillator, the state of charge can be checked using the indicator. It is checked with the working status of the defibrillator. However, since the electrode is separate from the defibrillator, the validity of the electrode must be checked separately by its expiry date. Therefore, to ensure the working condition of the electrode, the manager should know the periodic replacement plan. Additionally, in cases where the AED is installed with external, non-governmental financial support, there is often no financial plan for replacement of defibrillator accessories. In such cases, even if the AED manager or inspector finds a problem with the pads, the problem cannot be fixed. In this regard, when purchasing a defibrillator and installing it in a public place, it is necessary to establish a supply or financial plan for the maintenance of its accessories as well as an inspection plan. .

The use of AEDs in public places is related to the number of cardiac arrests in the facility area, the willingness of bystanders to use AEDs, and the 24-hour use of AEDs.^17,18,19. AEDs are very accessible during the week, but their accessibility decreases in the evening, including at night, and on weekends. This limitation in accessibility is associated with the reduced use of AEDs²⁰. As observed in our study, 24-hour accessibility was limited for AEDs installed in locations that were not open 24 hours a day, such as multipurpose facilities, schools, public buildings, and wellness facilities. . In addition, we found that the proportion of accessibility of less than 24 hours was highest in residential settings. The limited use of AEDs in residential settings can be a major barrier to the PAD program. Only about 1% of AEDs have been used. This low rate of use could be associated with low 24/7 accessibility. Thus, when planning the installation of the AED, it is necessary to consider whether the installation site is open 24 hours a day. In case the AED is installed in a place that is not open 24 hours a day (eg schools), the installation of the AED on the walls outside the buildings can be considered. Further studies to investigate structural and non-structural factors that influence low AED use are needed.

This study has several limitations. The results of this study cannot be generalized to other countries because the regulations for the implementation and maintenance of AEDs are based on the laws in force in each country. Since only AEDs funded by the city of Seoul and not all AEDs in Seoul were included in this study, the spatial density of AEDs in the catchment area and spatial deviations in AED coverage were not considered. taken into account. Other important factors that affect AED accessibility, such as socio-economic status, rural/urban setting, or EMS stations, were not analyzed. Therefore, this study may lack a holistic context of AED accessibility. There is an EMS-connected alert system using a smartphone app in South Korea. However, the effect of this system’s performance on AED accessibility and usability was not considered in the study. New AEDs were introduced during the study period, and the environmental and maintenance condition of the newly introduced AED may have contributed to the improvement in the overall maintenance condition. The inspectors being recruited annually, the same inspectors did not check the defibrillators during the study period. To reduce the bias caused by the inspectors, recruited inspectors were trained in the inspection method. It is possible that their judgment of the study criteria changed over time as their inspection process evolved because some inspectors remained the same during the study period.

In conclusion, although AEDs were in a relatively good state of maintenance, a significant proportion of public AEDs were not available for 24-hour use. Invalid pads and less than 24-hour accessibility were the main reasons limiting the 24-hour use of public AEDs. Community attention and initiatives are needed to increase the round-the-clock usability of public AEDs.