PURPOSE OF REVIEW: The most current practice guidelines for cardiopulmonary resuscitation published by the American Heart Association and European Resuscitation Council have placed the highest priority on achieving the most optimal circulation possible following sudden cardiac arrest through the delivery of early, consistent, high-quality and infrequently interrupted chest compressions during resuscitative efforts. The purpose of this review is to analyze the most recent trials involving adjunct mechanical devices designed to optimize blood flow to vital organs during cardiopulmonary resuscitation conditions. RECENT FINDINGS: Six devices show substantial promise based on the compelling results of numerous animal and small-scale clinical trials. All of these promising interventions, however, have yet to be validated in definitive clinical trials, particularly those examining long-term survival and neurological function. SUMMARY: Markedly enhanced circulation during cardiopulmonary resuscitation efforts has been found to be a critical element for effecting successful resuscitation. Preliminary studies of adjunct mechanical cardiopulmonary resuscitation devices have revealed significant increases in improved hemodynamics in both animal models and human studies, as well as improvements in short-term human survival in the clinical setting. Several of these devices are currently undergoing definitive clinical trials that hopefully will establish irrefutable efficacy and improved long-term neurological outcomes.