Abstract P176: How Much Can Hands-off Time Be Reduced by Performing Rhythm Analysis During CPR?
Background: Reducing interruptions in chest compressions (CC) is emphasized in current resuscitation guidelines and may improve outcome. There are several reasons to interrupt CC during automated external defibrillator (AED) use; one is the need to not touch the patient during AED rhythm analysis. A previous report indicated that a new algorithm for Analysis During CPR (ADC) can eliminate most analysis pauses, while maintaining high analysis accuracy. In the present study, we estimate how much the overall hands-off time could be reduced by implementing ADC in AEDs.
Methods: We analyzed a series of 77 AED recordings collected from two EMS systems from cases of out-of-hospital cardiac arrest featuring Guidelines 2005-compliant CPR. For each actual AED rhythm analysis preceded by a prompted CPR interval, a matching ADC shock-advisory decision was determined based on data from the interval just prior to the AED-prompted analysis pause. The overall hands-off ratio for each case (cumulative time without CC/recording length) and the duration of each analysis pause (interval from last CC to announcement of analysis decision) were measured by commercial post-event review software using impedance traces. To determine ADC impact in each case, the duration of analysis pauses eliminated by ADC was subtracted from the measured hands-off time. Reported data are median [25th, 75th percentiles].
Results: The median AED recording duration was 6.2 [3.4, 10.7] minutes, yielding 224 pairs of actual AED and simulated ADC analyses. The ADC algorithm found the ECG to be too noisy for 34 analyses (15%), requiring a CC pause for traditional hands-off AED analysis. For the remaining 190 analyses, ADC obviated the need for an analysis pause, correctly identifying coarse VF in 22 of 23 analyses, and non-shockable rhythms in 163 of 166 analyses. By eliminating 85% of analysis pauses, representing 25% [16%, 31%] of the overall hands-off time, ADC would have decreased the hands-off ratio across the 77 cases from 33% [25%, 40%] to 24% [19%, 31%] (p<0.001).
Conclusions: AEDs capable of accurate rhythm analysis during ongoing CPR can significantly contribute to the objective of minimizing CC interruptions, and may thus improve patient outcomes.