Abstract P200: Optimal Phase Relationship Between Defibrillation and Manual Chest Compression Improves Shock Success
Introduction A newly developed blanket provides the protection for rescuer from shock during cardiopulmonary resuscitation (CPR) and allow for uninterrupted chest compression. We examined relationships between the phase of manual compression and the timing of defibrillation based on measurement of the 50% defibrillation threshold (DFT50).
Methods Ventricular fibrillation (VF) was electrically induced and untreated for 10 seconds in 8 domestic male pigs weighing between 22–31 kg. The depth and frequency of manual chest compression utilizing the isolated blanket initiated and continued for 25 seconds guided by a CPR prompter (iCPR, ZOLL Medical Corporation, Chelmsford, MA). A biphasic electrical shock of variable energies ranging from 30~150J was delivered at 5 phases of the compression period as shown in Figure 1–A⇓. A group in which defibrillation was attempted at a constant 2 seconds following discontinued of chest compression served as a control.
Results No difference between coronary perfusion pressures (CPP) prior to delivering of the shock were observed between the 6 groups. The calculated energy required for defibrillation, however, was significantly lower during the latter half of decompression as represented by group C and D (Figure 1–B⇓).
Conclusion Defibrillation efficacy is maximal when an electrical shock is delivered during the latter phase of decompression.