Can we predict defibrillation success during cardiac arrest?

Ristagno Giuseppe, Milan

  • Coarse VF responds well to defibrillation; intermediate and fine VF – not as well
  • Defibrillation failure approaches ~75% during CPR
  • Current shockable algorithm considers all shockable situations the same and uses the time approach (Shock –> 2 min CPR –> Shock)
  • Recurrent VF /Resistant VF–> multiple defib attempts –> worse myocardial dysfunction post ROSC. Improving defib success will reduce the number of attempts and the post ROSC myocardial dysfunction
  • ECG waveform analysis during CPR can be used to individualize defibrillation attempts to improve success
  • AMplitude Spectrum Area (AMSA), one such technique, gives the area under the amplitude and frequency curve obtained from rhythm analysis during CPR
  • Higher the AMSA –> higher are the chances of successful defibrillation
  • With good chest compressions AMSA improves over time –> improved defibrillation success
  • AMSA >15.5 predicts defibrillation success and <6.5 predicts failure

  • Immediate vs delayed Defib in shockable rhythm – no superiority of one approach over the other (Cochrane meta-analysis – 2014)
  • AMSA trial ongoing. Analysis of data from the first 30 patients – quite promising (see screen shot below)
  • This might change the way we defibrillate in future!