Public-access defibrillator density and clinical outcomes after out-of-hospital cardiac arrest: a nationwide cohort study
Y Ohnaga, Y Saito, K Tateishi, H Kitahara, Y Mori, T Matoba, N Yonemoto, Y Tahara, Y KobayashiAbstract
Background
Previous studies in the 2010s showed that a higher geographic density of public-access defibrillators (PADs) was associated with better clinical outcomes after out-of-hospital cardiac arrest (OHCA); around 2010, the density of PADs was approximately 1/km². Since then, access to PADs has improved in many developed countries and regions, in parallel with advances in bystander cardiopulmonary resuscitation and post-cardiac arrest care. It remains unclear whether further increases in PAD density are associated with improved outcomes after OHCA in the current era.
Purpose
To evaluate the relationship between the PAD density and clinical outcomes of patients with witnessed OHCA in Japan, one of the world’s leading countries in the availability of PAD.
Methods
Using nationwide registry data (All-Japan Utstein Registry), patients with bystander-witnessed OHCA who underwent resuscitation attempts in Japan in 2023 were included. We evaluated the associations between the number of PADs per square kilometer of inhabited area and the probability of prehospital return of spontaneous circulation (ROSC), 1-month overall survival, and 1-month neurologically favorable survival, defined as cerebral performance category score of 1 or 2.
Results
A total of 32,310 patients were analyzed in the present study. The mean (standard deviation) age was 77.4 (14.8) years, and men accounted for 59.6%. The density of PADs was 4.3/km2 in Japan. Overall, 5,326 (16.5%), 2,606 (8.1%), and 1,299 (4.0%) had prehospital ROSC and 1-month survival and neurologically favorable survival, respectively. Higher PAD density per square kilometer was associated with a greater proportion of patients achieving ROSC and 1-month survival, while the increase in the probability of a favorable neurological outcome at 1 month remained minimal compared to the other outcomes (Figure).
Conclusions
The present nationwide registry study demonstrated a high density of PADs in Japan. In the current era, however, the association between the widespread availability of PADs and neurologically favorable outcomes after OHCA appeared to have plateaued, yet its positive association with a probability of prehospital ROSC remained. These findings highlight the uncertainty regarding whether further increases in PAD density readily translate into improved prognosis in patients with witnessed OHCA.Figure