Mechanical CPR (cardiopulmonary resuscitation) devices help performing correct chest compressions in the event of a cardiorespiratory arrest. These devices are comfortable and useful, they keep chest compression following the recommendations as they do not depend on interpersonal variability, they do not get tired, their use is simple and one of the rescuers is released from this task, thus facilitating the assistance. Besides, their use in transport conditions makes it safer. However, when coming to results, these mechanical CPR devices have not clearly demonstrated such an advantage, neither in the field of cardiac arrest, nor in organ preservation in the case of donors after cardiac death. In donors after cardiac death they are widely used by most of the emergency services involved, but a number of injuries produced in lungs during the early years of their use have made it controversial. In this paper we make a review of the road traveled by mechanical CPR devices and of the main articles which mark the way.