The need to resume chest compressions immediately after defibrillation attempts: An analysis of post-shock rhythms and duration of pulselessness following out-of-hospital cardiac arrest

Aim: Current consensus guidelines for cardiopulmonary resuscitation (CPR) recommend that chest compressions resume immediately after defibrillation attempts and that rhythm and pulse checks be deferred until completion of 5 compression:ventilation cycles or minimally for 2 min. However, data specifically confirming the post-shock duration of asystole or pulseless electrical activity before return of spontaneous circulation (ROSC) are lacking. Our aim was to describe the frequency of the various post-shock cardiac rhythms and the duration of post-shock pulselessness in out-of-hospital non-traumatic cardiac arrest. Method: Using prospectively-collected data from the Resuscitation Outcomes Consortium (ROC) Epistry database, the investigators reviewed monitor-defibrillator recordings of 176 patients who received defibrillation attempts in the out-of-hospital setting for ventricular fibrillation (VF) or ventricular tachycardia (VT) with absent pulses,. Results: Among 376 different defibrillation attempts delivered in the 176 patients, there were 182 resulting episodes of post-shock asystole. The mean interval of asystole after defibrillation was 69 ± 136 s (median 20 s; IQR 36) and the mean interval for return of an organized rhythm was 64 ± 157 s (median 7 s; IQR 26). The mean time to ROSC was 280 ± 320 s (median 136 s; IQR 445). Conclusion: After defibrillation attempts, the majority of patients remain pulseless for over 2 min and the duration of asystole before return of pulses is longer than 120. s beyond the shock gap in as many as 25%. These data support the recommendation to immediately resume chest compressions for 2 min following attempted defibrillation.