Abstract 253: Decline In Initial Shockable Rhythm In Patients Treated With Public Access Defibrillators Over A 10-year Period

Abstract

Introduction: Previous analysis of emergency medical services manual defibrillator recordings suggests that the proportion of patients with initial shockable rhythms during out-of-hospital cardiac arrest is decreasing over time. This analysis aims to determine if this decline also occurs in public access defibrillator data. Methods: Worldwide post-market data from HeartSine SAM PAD public access defibrillators was collected between 2012 and 2022. Presence of an initial shockable rhythm (ventricular fibrillation or ventricular tachycardia) was determined by the device algorithm decision and clinical overread. The proportion of patients who presented an initial shockable rhythm each year was calculated. Data was analysed using Minitab. Summary statistics were calculated for patient age and gender, and a logistic regression model was used to examine the proportion of initial shockable rhythm over time. Results: A total of 5404 patient events were collected. Seventy-four percent were male, and mean (SD) age was 61.2 (18.2) years. Proportion of initial shockable rhythm as a response to year was assessed, and occurrence of shockable rhythms decreased by approximately 6% per year [OR: 0.94, 95%CI (0.91, 0.96), p<0.001]. Conclusion: In line with findings from emergency service resuscitation attempts, the proportion of initial shockable rhythms in patients treated with a public access defibrillator declined over a ten-year period.