Abstract 66: The Duration of Asystole Before Return of an Organized Rhythm or Spontaneous Circulation After Defibrillation
Background: Defibrillation success has been traditionally defined as termination of ventricular fibrillation five seconds after the shock. The current American Heart Association guidelines for Cardiopulmonary Resuscitation (CPR) recommend that chest compressions resume immediately after defibrillation and to perform rhythm and pulse checks after 5 cycles of CPR. Few studies have reported the duration of asystole after defibrillation before return of an organized rhythm or return of spontaneous circulation (ROSC).
Objective: To describe the duration of asystole before return of an organized rhythm or ROSC after defibrillation during out-of-hospital (OOH) non-traumatic cardiac arrest.
Methods: This observational study analyzed Dallas-Fort Worth ROC site data collected in the Resuscitation Outcomes Consortium (ROC) Epistry database. We reviewed monitor-defibrillator recordings of patients who were defibrillated for ventricular fibrillation or pulseless ventricular tachycardia during OOH cardiac arrest. We analyzed the duration of asystole after defibrillation before return of an organized rhythm or ROSC. An organized rhythm was defined as similar QRS complexes that produce a consistent rhythm without a palpable pulse.
Results: A total of 176 patients were defibrillated after OOH cardiac arrest from November 2009 to April 2011. Mean age was 61 ± 17 years and 66.6% were male. The mean interval of asystole after defibrillation was 56 ± 144 sec (0 - 1098 sec), median 6 sec (IQR 29). The mean time to return of an organized rhythm after defibrillation was 64 ± 157 sec, median 7 sec (IQR 26). The mean time to ROSC after defibrillation was 280 ± 320 sec, median 136 sec (IQR 445). ROSC occurred in 51 (29%) patients and 16% survived to hospital discharge. The defibrillation energy that resulted in ROSC were as follows: twenty-nine at 200 Joules, eight at 300 Joules, nine at 360 Joules, one at 70 Joules, and 4 in the Emergency Department.
Conclusion: The post-shock duration of asystole before return of an organized rhythm or ROSC is longer than 30 seconds in 25% of patients. Our findings support the recommendation to immediately resume chest compressions following attempted defibrillation and to continue CPR for two more minutes before checking the rhythm.
- Cardiac arrest
- Cardiopulmonary resuscitation
- Ventricular defibrillation
- Electric countershock
- © 2011 by American Heart Association, Inc.