Effect of Automated External Defibrillator Cardiopulmonary Resuscitation Protocol on Outcome From Out-of-Hospital Cardiac Arrest - DEFI 2005


The goal of the trial was to evaluate two automated external defibrillator (AED) protocols among patients with out-of-hospital cardiac arrest due to ventricular fibrillation. The control protocol was based on the Guidelines 2000, which limited cardiopulmonary resuscitation (CPR) to less than 50% of AED connection time. The study protocol featured more CPR due to elimination of stacked shocks and less rhythm analysis.


An AED protocol that allows for more CPR would improve outcomes.

Study Design

  • Parallel

Patients Screened: 5,107
Patients Enrolled: 845
Mean Follow Up: 1 year
Mean Patient Age: 65 years
Female: 22%

Patient Populations:

  • Patients at least 18 years of age who suffered an out-of-hospital cardiac arrest due to ventricular fibrillation


  • Cardiac arrest due to trauma
  • Inability to obtain consent
  • Multiple victims were simultaneously treated by a single Basic Life Support team

Primary Endpoints:

  • Survival to hospital admission

Secondary Endpoints:

  • Return of pulse before physician arrival
  • Survival to hospital discharge
  • Survival to 1 year
  • Hemothorax from CPR that resulted in need for chest tube drainage

Drug/Procedures Used:

Patients who suffered an out-of-hospital cardiac arrest were randomized to AED study protocol with more CPR (n = 421) versus standard control protocol (n = 424).

Principal Findings:

Overall, 845 patients were randomized. In the study group, the mean age was 65 years, 22% were women, arrest location was the home in 56%, mean response time (call to AED power on) was 10.5 minutes, and mean shock time (AED power on to shock) was 85 seconds.

The number of shocks delivered was 2.5 in the study group versus 2.9 in the control group (p < 0.001), preshock pause was 9 seconds versus 19 seconds (p < 0.001), postshock pause was 11 seconds versus 33 seconds (p < 0.001), and the CPR hands-on ratio was 61% versus 48% (p < 0.001), respectively.

The occurrence of the primary outcome, survival to hospital admission, was 43.2% in the study group versus 42.7% in the control group (p = 0.87). Return of pulse before physician arrival was 47.0% versus 48.6% (p = 0.65) and survival to hospital discharge was 13.3% versus 10.6% (p = 0.20), respectively.


Among patients with out-of-hospital cardiac arrest due to ventricular fibrillation, the use of a new AED protocol was successful at increasing CPR time and reducing pre- and postshock pauses. Despite more CPR, survival to hospital admission and discharge was similar between the groups. The overall prognosis of cardiac arrest patients remains poor.


Jost D, Degrange H, Verret C, et al. DEFI 2005: a randomized controlled trial of the effect of automated external defibrillator cardiopulmonary resuscitation protocol on outcome from out-of-hospital cardiac arrest. Circulation 2010;121:1614-22.

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, SCD/Ventricular Arrhythmias

Keywords: Defibrillators, Out-of-Hospital Cardiac Arrest, Cardiopulmonary Resuscitation, Ventricular Fibrillation

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