Timing of Public-Access Defibrillation for Patients With Out-of-Hospital Cardiac Arrest: A Nationwide Cohort Study...

Area of Science:

• Cardiology
• Emergency Medicine
• Public Health

Background:

• Early defibrillation is critical for improving survival rates in out-of-hospital cardiac arrest (OHCA) cases involving ventricular fibrillation (VF).
• While public-access defibrillation (PAD) benefits are known, their effectiveness relative to intervention timing requires further evaluation.
• This study investigates how the timing of PAD intervention influences patient outcomes.

Purpose of the Study:

• To assess the impact of public-access defibrillation (PAD) timing on survival and neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients.
• To determine if the effectiveness of PAD varies based on when defibrillation is administered before emergency medical services (EMS) arrival.
• To analyze the association between PAD and favorable neurological outcomes using a nationwide registry.

Main Methods:

• A nationwide, prospective, population-based OHCA registry in Japan (2022-2023) was utilized.
• Consecutive cases of bystander-witnessed VF in public locations with resuscitation attempts were included.
• Patients receiving PAD before EMS arrival were matched with similar at-risk patients using time-dependent propensity scores to control for resuscitation time bias. The primary outcome was 1-month survival with favorable neurological outcome (Cerebral Performance Category scale 1 or 2).

Main Results:

• 1664 matched pairs of patients were identified after sequential matching.
• Public-access defibrillation (PAD) was associated with a 1.46-fold increased likelihood of 1-month survival with favorable neurological outcome compared to non-PAD cases (95% CI, 1.34-1.59).
• The positive effect of PAD on outcomes was observed across various intervention times, including 0-4 minutes (RR 1.33), 5-9 minutes (RR 1.49), 10-14 minutes (RR 1.55), and 15-19 minutes (RR 2.46), though with wider confidence intervals for later times.

Conclusions:

• In Japan, public-access defibrillation (PAD) administered before emergency medical services (EMS) arrival is significantly associated with improved neurological outcomes for patients experiencing bystander-witnessed ventricular fibrillation in public locations.
• The study demonstrates a consistent positive association between PAD and better outcomes, irrespective of the time to EMS arrival.
• These findings support the implementation and accessibility of PAD devices in public spaces to enhance cardiac arrest survival rates.