Shock advisory system with minimal delay triggering after end of chest compressions: accuracy and gained hands-off time.
OBJECTIVE
Shortening hands-off intervals can improve benefits from defibrillation. This study presents the performance of a shock advisory system (SAS), which aims to decrease the pre-shock pauses by triggering fast rhythm analysis at minimal delay after end of chest compressions (CC).


METHODS
The SAS is evaluated on a database of 1301 samples from 311 out-of-hospital cardiac arrests (OHCA) from automated external defibrillators (AEDs). The following rhythms are identified: 788 asystoles (ASYS), 20 normal sinus rhythms (NSR), 394 other non-shockable rythms (ONS), 81 ventricular fibrillations (VF), 18 rapid ventricular tachycardias (VThi). SAS is launched in two-stages: first stage for accurate detection of actual end of CC (ReEoCC); second stage for early "Shock"/"No-Shock" decision by using all available artifact-free ECG signals after REoCC during 3, 5, 7 s.


RESULTS
Performance of the presented SAS versus AEDs is compared. The median hands-off time gained from earlier starting of ECG analysis is 5.8 s and for earlier shock advice is 12.5 s to 8.5 s when SAS rhythm analysis lasts 3 s to 7 s. The SAS accuracy at 3-7 s is: specificity 97.7-98.9% (ASYS), 100-100% (NSR), 98.5-99.2% (ONS); sensitivity 91.4-98.8% (VF), 88.9-96.7% (VThi).


CONCLUSIONS
This study indicates that shortening the pre-shock hands-off pause by more efficient management of the SAS process in AEDs is possible. For analysis duration of 5 s (7 s), the delay between the end of chest compressions and the shock advice can be reduced by 10.5 s (8.5 s) median, while AHA requirements for rhythm detection accuracy are met. The use of this solution in AEDs could provide more reliable rhythm analysis than methods applying filtering techniques during CC.
Schiller Médical SAS, 4 rue L. Pasteur, F-67160 Wissembourg, France. jean-philippe.didon@schiller.fr
Jean-Philippe
JP
Didon
Vessela
V
Krasteva
Sarah
S
Ménétré
Todor
T
Stoyanov
Irena
I
Jekova
D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D047548:Defibrillators / Q000592:standards*; D004562:Electrocardiography; D006336:Heart Massage / Q000379:methods*; D006339:Heart Rate; D006801:Humans; D058687:Out-of-Hospital Cardiac Arrest / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000150:complications / Q000503:physiopathology / Q000628:therapy*