Abstract 147: Appropriate Frequency of Defibrillation for Ventricular Fibrillation in Cardiogenic Out-of-Hospital Cardiac Arrest Patients
It is well known that ventricular fibrillation (VF) is a fatal arrhythmia, and
the success rate of defibrillation decreases rapidly with time passed from the collapse.
Chest compression has to be interrupted during rhythm analysis or shock, and
this discontinuance is reported to be nocuous. The average time required from
perception to contact by an emergency medical service (EMS) is seven to eight
minutes. This study aimed to determine the appropriate frequency of
defibrillation for VF on out-of hospital cardiac arrest patients.
We referred to a database of a nationwide, population-based registry of
out-of-hospital cardiac arrests that was compiled by the Fire and Disaster
Management Agency of Japan between 2005 and 2010. The target of this study were
cardiogenic cardiac arrest patients where a witness was present, the initial ECG
was VF, and the duration from the collapse to the initial shock by the EMS was
less than 10 minutes. We evaluated the rate of return of spontaneous
circulation (ROSC) or survival at 1 month with good or moderate
cerebral performance (Cerebral Performance Category; CPC 1-2) in order to examine the appropriate frequency of
A total of 670,313 patients were registered and 13,411 patients became the
object of this study. The average age was 64±15 years old (80% men). Duration
from collapse to the initial defibrillation was 6.4±3.1 minutes, and average
frequency of defibrillation was 2.3±1.6 times. Efficacy rate of the shock was
37%, 78% of which succeeded up to the second trial. ROSC was 37% and rate of
CPC1-2 patient after 1 month survival was 33%. Defibrillation frequency and
ROSC in the ROC curve shows a cutoff value of 1.5 times, sensitivity of 63%,
specificity of 53%, P<0.001, and
95% confidence interval (0.63-0.66). Defibrillation frequency and acquisition
rate of CPC1-2 in the ROC curve shows a cutoff value of 1.5 times, sensitivity
of 62%, specificity of 52%, P<0.001
and 95% confidence interval (0.58-0.60).
ROSC and rate of CPC1-2 patient shows that the cutoff value for apposite
frequency of shock for VF on out-of-hospital cardiac arrest patients was 1.5
times. This study suggests the necessity of considering the frequency of
defibrillation at the time of transporting the patient.
- © 2012 by American Heart Association, Inc.