Prehospital emergency care
October 6, 2026 · via Europe PMC
Bystander AED effectiveness despite low utilisation in OHCA.
Sohn Y, Cho G, Cho Y, Park T, Korean Cardiac Arrest Research Consortium (KoCARC) Investigators.
AI summary — for doctors, generated from the abstract only
When bystanders did apply an AED in Korean out-of-hospital cardiac arrest, survival and neurological outcomes were better than with no defibrillation, but AEDs were rarely used, especially in residential settings.
What was studied
Retrospective analysis of a prospective multicentre Korean OHCA registry (October 2015 to June 2025; 23,918 adults of presumed medical cause) comparing bystander AED application (n = 383), EMS-delivered shock without bystander AED (n = 5,975) and no prehospital defibrillation as the reference (n = 17,560), using multivariable, propensity-score and weighted analyses.
Key findings
- Bystander AED was associated with improved survival to discharge (aOR 1.60; 95% CI 1.19-2.14) and good neurological outcome (aOR 2.31; 1.65-3.23) versus no defibrillation
- Using a pooled control group that mixed EMS-shocked and non-shocked patients shrank the estimates to non-significance (survival 1.09; neurological 1.14)
- Effectiveness did not differ by location (interaction P 0.15 or higher), but bystander AED was applied in 8.5% of public-area versus 1.9% of non-public opportunity cases, a 4.5-fold gap
Clinical relevance
The main barrier to benefit appears to be getting AEDs applied, not device effectiveness, particularly at home. The authors argue residential rapid-activation infrastructure deserves policy priority alongside continued device placement.
Who should care
Limitations
Observational registry data from one country, so residual confounding and selection of who receives a bystander AED cannot be excluded. Only 383 cases involved a bystander AED, limiting precision in subgroups.
Bystander AED use is associated with better outcomes when it happens; closing the deployment-to-use gap, especially in residences, is the priority.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Objectives
Observational estimates of bystander automated external defibrillator (AED) effectiveness are inconsistent in settings with mature public-access defibrillation infrastructure but low utilisation, partly because the conventional reference group pools emergency medical services (EMS)-shocked with non-defibrillated patients. We estimated bystander AED effectiveness against a partitioned no-defibrillation reference, tested effect modification by location, and quantified the deployment-utilisation gap.
Methods
Retrospective analysis of a prospectively collected multicentre out-of-hospital cardiac arrest (OHCA) registry (Korea, October 2015-June 2025; 23,918 adults of presumed medical aetiology). A three-tier prehospital defibrillation-provider variable was defined: bystander AED applied (n = 383); EMS-delivered shock without preceding bystander AED (n = 5,975); and no prehospital defibrillation (reference; n = 17,560). Primary outcomes were survival to discharge and good neurological outcome (Cerebral Performance Category 1-2), analysed by multivariable logistic regression with propensity-score, inverse-probability-weighting and location-stratified secondary analyses.
Results
Bystander AED application was associated with improved survival (adjusted odds ratio [aOR] 1.60; 95% CI 1.19-2.14) and good neurological outcome (2.31; 1.65-3.23), comparable to that of EMS-delivered shock; the pooled-control specification attenuated estimates to non-significance (survival 1.09; neurological 1.14). Shock-delivered applications significantly exceeded EMS-delivered shock for neurological outcome (aOR 1.43; P = 0.03). Effectiveness did not differ by location (interaction P ≥ 0.15). Bystander AED was applied in 8.5% of Public-area versus 1.9% of Non-public AED-opportunity cases - a 4.5-fold gap.
Conclusions
Bystander AED was associated with improved outcomes when applied, comparable to or exceeding EMS-delivered shock; the dominant constraint was the deployment-utilisation gap, greatest in residential settings. Residential rapid-activation infrastructure warrants policy priority alongside, not instead of, continued device placement.
DOI
10.1080/10903127.2026.2743854
PMID
42837514
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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