Miniaturization of a Chest Compressor for Cardiopulmonary Resuscitation

A miniaturized chest compressor (MCC®) for cardiopulmonary resuscitation (CPR) was designed to serve as a compact portable device to overcome limitations of manual chest compression and of currently marketed mechanical devices. We sought to especially address constraints of size and weight of current devices, together with the need for ease of application and consistent compressions with appropriate force and depth. We further intended that the device allows for ease of evacuation and transport through small spaces. These objectives are responsive to the increasingly recognized requirements for uninterrupted chest compression including that which results from operator fatigue during manual compressions. Utilizing a garment applied to the torso, the device incorporated a telescopic piston for chest compression. The compressor was pneumatically powered so as to avoid the added weight and potential electrical adversity of power delivered by batteries. Pneumatic power was supplied by the same compressed air or oxygen tank, which is routinely carried by professional emergency medical rescuers. The MCC® was tested on a porcine model during cardiac arrest and resuscitation with comparisons to the current industry standard, the Michigan Thumper®. Arterial, carotid, and coronary perfusion pressures, together with end-tidal carbon dioxide as a surrogate for cardiac output, were measured. The MCC® threshold levels of pressure, flow, and end-tidal $PCO2$ are achieved, which were predictive of successful defibrillation with restoration of spontaneous circulation. We conclude that the MCC® is as effective as that of the established industry standard, the Michigan Thumper®, with the potential advantage of portability and facile application, especially for out-of-hospital resuscitation.