Defibrillator charging before rhythm analysis causes peri-shock pauses exceeding guideline recommended maximum 5 s : A randomized simulation trial.

INTRODUCTION

Charging defibrillators prior to analyzing heart rhythms may decrease the no-flow time during rhythm check pauses while resuscitating in cardiac arrest. Although this anticipatory method is already used in some centers little is known about its safety. This study was carried out to confirm the safety and feasibility of the anticipatory method. It was hypothesized that this anticipatory method results in shorter total no-flow times, while other parameters of defibrillation efficacy including defibrillator safety and minimization of peri-shock pauses are unchanged.

METHODS

This manikin study assigned 243 medical students randomly to study groups, 121 to the anticipatory method and 122 to the recommended European Resuscitation Council (ERC) algorithm. Of these 237 students ultimately underwent training (112 anticipatory method vs. 125 ERC algorithm). Participants were assessed and video recorded during a simulated cardiac arrest scenario which included three different heart rhythms (ventricular fibrillation [VF], pulseless ventricular tachycardia [pVT], asystole) in randomized order. Video and software analyses were performed. Defibrillation safety was assessed using a 17-item checklist defined beforehand.

RESULTS

A total of 203 simulated cardiac arrests (75 anticipatory method and 128 ERC 2010 algorithm) were analyzed. The anticipatory method did not significantly reduce no-flow time (25.8 s, standard deviation, SD 7.4 s vs. 27.4 s SD 8.4 s, p = 0.19); however, peri-shock pauses were significantly longer in the anticipatory group compared to the ERC 2010 group (9.5 s SD 2.8 s vs. 3.3 s SD 1.9 s, p < 0.001). No significant difference concerning defibrillation safety between the groups was observed according to the 17-item checklist (14.6 SD 1.6 vs. 15.0 SD 1.4, p = 0.07).

CONCLUSION

Charging defibrillators before rhythm analysis did not decrease total no-flow time in simulated cardiac arrests but resulted in significantly longer peri-shock pauses exceeding 5 s. No significant differences in defibrillation safety were observed between the groups.