The effects of a newly developed miniaturized mechanical chest compressor on outcomes of cardiopulmonary resuscitation in a porcine model*

OBJECTIVE: When the duration of cardiac arrest is prolonged, reperfusion of the vital organs by effective chest compression is the most important intervention for successful resuscitation. We investigated the effects of a newly developed miniaturized chest compressor on the outcomes of cardiopulmonary resuscitation. DESIGN: Prospective, randomized, controlled experimental study. SETTING: University-affiliated animal research laboratory. SUBJECTS: Thirty male domestic pigs. INTERVENTIONS: Ventricular fibrillation was induced in 30 male domestic pigs weighing 35 ± 2 kg. Cardiopulmonary resuscitation was initiated after 7 mins of untreated ventricular fibrillation. The animals were randomized to receive mechanical chest compression with a miniaturized chest compressor, a LUCAS device or a Thumper device. After 5 mins of cardiopulmonary resuscitation, a 150-J defibrillation was delivered. If resuscitation was not successful, cardiopulmonary resuscitation was continued for 2 mins before the next defibrillation. The protocol was continued until successful resuscitation or for a total of 15 mins of cardiopulmonary resuscitation. The animals were observed for 72 hrs after resuscitation. MEASUREMENTS AND MAIN RESULTS: The miniaturized chest compressor generated significantly greater coronary perfusion pressure, end-tidal PCO2, carotid blood flow, and intrathoracic negative pressure, with significantly lower compression depth and fewer rib fractures when compared with both the LUCAS and Thumper devices. Both the miniaturized chest compressor and LUCAS devices required lower numbers of defibrillation for successful resuscitation when compared with the Thumper device. This was associated with lower prevalence of recurrent ventricular fibrillation and better postresuscitation myocardial and neurological function when compared with the Thumper device. CONCLUSIONS: The miniaturized chest compressor improves hemodynamic efficacy and the success of cardiopulmonary resuscitation with significantly less injury, which is as effective as the LUCAS device. It may provide a new option for cardiopulmonary resuscitation.