Current is better than energy as predictor of success for biphasic defibrillatory shocks in a porcine model of ventricular fibrillation

Giuseppe Ristagno, Tao Yu, Weilun Quan, Gary Freeman, Yongqin Li

Research output: Contribution to journalArticle

Abstract

Objective: The evidence that monophasic defibrillation success is mainly determined by current is secure. However, modern defibrillators use biphasic waveforms. The aim of this study was to compare energy, peak voltage and peak current in predicting biphasic shock success in a porcine model of ventricular fibrillation (VF) where the impedance varies within a wide of ranges. Methods: In 14 domestic male pigs weighing between 27 and 38. kg, VF was electrically induced and untreated for 15. s. Animals were randomized to receive defibrillation attempts from one of two defibrillators with different impedance compensation methods. A grouped up-and-down defibrillation threshold testing protocol was used to maintain the average success rate in the neighborhood of 50%. After a recovery interval of 5. min, the testing sequence was repeated for a total of 60 test shocks for each animal. Results: A high defibrillation success was observed when high peak current was delivered. The area under ROC curve for predicting shock success was 0.681 for peak current, 0.585 for peak voltage and 0.562 for energy. The odds ratio revealed that peak current was a better predictor (OR = 1.321, p<0.001) for defibrillation outcome compared with energy (OR = 0.979, p<0.001) and peak voltage (OR = 1.000, p= 0.69) when multivariable logistic regression was conducted. Conclusion: In this porcine model of VF within a wide range of transthoracic impedance, peak current was a better indicator for shock success than the currently used energy for biphasic defibrillatory shocks. This finding may encourage design of new current-based biphasic defibrillators.

Original languageEnglish
Pages (from-to)678-683
Number of pages6
JournalResuscitation
Volume84
Issue number5
DOIs
Publication statusPublished - May 2013

Keywords

  • Cardiac arrest
  • Current based defibrillation
  • Energy based defibrillation
  • Impedance compensation
  • Shock success
  • Ventricular fibrillation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Emergency
  • Emergency Medicine

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