Prognostic significance of field response in out-of-hospital ventricular fibrillation.

We reviewed 94 cases of prehospital ventricular fibrillation (VF) to determine aspects of field response that predicted outcome. Only one of 37 patients (3 percent) failing to achieve rhythms other than VF or asystole after the first two defibrillations survived to hospital discharge compared to nine of 57 (16 percent) achieving organized rhythms by this point (p less than 0.05). None of 56 patients failing to achieve pulses prior to transport survived to hospital discharge compared to ten of 38 achieving field pulses (p less than 0.01). However, survival to discharge was not significantly different between patients who developed pulses immediately with their rhythms (5 of 17, 29 percent) and those who were defibrillated into pulseless rhythms but later developed pulses in the field (five of 21, 24 percent). Thus, for prehospital VF, the best field response identifies potential survivors prior to hospital arrival. In addition, the frequent occurrence and potentially favorable outcome of an initially pulseless rhythm necessitates reevaluation of current therapy.