An Analysis of Electrical Current Flow Through Rescuers in Direct Contact With Patients During Biphasic External Defibrillation
Background— Brief interruptions in chest compressions reduce the efficacy of resuscitation from cardiac arrest. Interruptions of this type are inevitable during hands-off periods for shock delivery to treat ventricular tachyarrhythmias. The safety of a rescuer remaining in contact with a patient being shocked with modern defibrillation equipment has not been investigated.
Methods and Results— This study measured the leakage voltage and current through mock rescuers while they were compressing the chests of 43 patients receiving external biphasic shocks. During the shock, the rescuer’s gloved hand was pressed onto the skin of the patient’s anterior chest. To simulate the worst case of an inadvertent return current pathway, a skin electrode on the rescuers thigh was connected to an electrode on the patient’s shoulder. In no cases were shocks perceptible to the rescuer. Peak potential differences between the rescuer’s wrist and thigh ranged from 0.28 to 14 V (mean 5.8±5.8 V). The average leakage current flowing through the rescuer’s body for each phase of the shock waveform was 283±140 μA (range 18.9 to 907 μA). This was below several recommended safety standards for leakage current.
Conclusions— Rescuers performing chest compressions during biphasic external defibrillation are exposed to low levels of leakage current. The present findings support the feasibility of uninterrupted chest compressions during shock delivery, which may enhance the efficacy of defibrillation and cardiocerebral resuscitation.
Received December 27, 2007; accepted February 20, 2008.