A study of factors associated with the prognosis of cardiac arrest patients in a depopulated area with a high elderly population transported by Shimoda Fire Department

To investigate the etiology of cardiac arrest in patients living in depopulated rural areas with a high elderly population in the Kamo region. We investigated patients with cardiac arrest who were transported by the Shimoda Fire Department between January 2019 and December 2021. The following patients' details were collected: circumstance, age, sex, cause of cardiac arrest, witnessed collapse, chest compression performed by bystanders, oral instruction, use of an automated external defibrillator (AED), initial rhythm, advanced cardiac life support provided by emergency medical technicians, and neurological outcomes. The patients were divided into two groups based on the return of consciousness (RC). We compared the variables above between the two groups. A total of 281 patients with cardiac arrest were included in this study. The participants were predominantly men (59.7%), and the average age was 76 years. AED was applied to eight patients at the scene; however, all eight did not have an initial shockable rhythm. RC was achieved in eight (2.8%) patients. The precise cause of cardiac arrest among the participants who achieved RC was cardiogenic, drowning, and suffocation in three, three, and two cases, respectively. The patients were significantly younger, and the ratio of securing a venous route and airway was significantly lower in the RC (+) group than in the RC (-) group. The ratio of helicopter emergency medical services (HEMS) in the RC (+) group was significantly greater than that in the RC (-) group. This study reported the etiology of cardiac arrest in patients living in a depopulated rural area of Japan with a high elderly population. The usefulness of an AED could not be proven; the cardiogenic cardiac arrest was not dominant among patients who achieved RC, and HEMS transport might be useful for obtaining RC.