Abstract 219: Combination of Algorithms to Decrease Preshock Pause for Automated External Defibrillators
BACKGROUND Long pre-shock ‘hands-off’ intervals without chest compressions (CC) are associated with defibrillation failure. Current guidelines recommend shortening the ‘hands-off’ intervals. The aim of this study is to present the performance of a Shock advisory System (SAS) which is designed for triggering a fast ECG analysis at minimal delay after the end of chest compression (EoCC).
METHOD A subset of 1263 strips is identified from 311 Out-of-hospital cardiac arrest (OHCA) interventions. AED rhythms include 1182 Non-Shockable strips (788 asystoles (ASYS), 394 other non-shockable rhythms (ONS)), and 81 ventricular fibrillations (VF). The SAS with minimum ‘hands-off’ intervals first detect the real end of CC (ReEoCC) offset considered as the earliest triggering point for a reliable ECG analysis without CC artifacts. Then, it performs a fast ECG analysis to lead to “Shock/No shock” decision. Specificity (Sp) for ASYS and ONS and sensitivity (Se) for VF are computed
RESULTS The ECG analysis is triggered immediately at ReEoCC. The gain in time for earlier starting of the ECG analysis is found to be 5.6±3.6 seconds. The accuracy of the SAS is tested for 6 seconds analysis duration. The SAS “Shock/No shock” decision is provided 10.6±3.9 seconds earlier than the current AED decision. The SAS performance is compared to the AHA recommendations for Sp, Se and 90% one-sided lower confidence limit (LCL90) for noise-free signals (Table 1).
CONCLUSION The accuracy of SAS for fast ECG analysis at minimal delay after the end of CC fulfills the AHA goals (Sp/Se and LCL90) for ASYS, ONS and VF rhythms. A reduction of ‘hands-off’ time of 10.6 seconds (between end of CC and end of analysis) in average can be expected, when compared to current AED decision delay. Table 1: Accuracy of SAS with minimum ‘hands-off’ intervals
- © 2011 by American Heart Association, Inc.