BACKGROUND AND OBJECTIVES: No existing device for cardiopulmonary resuscitation(CPR)isdesignedto exploit both the "cardiac pump" and the "thoracic pump" simultaneously. This study was designed to assess the hemodynamic effects of simultaneous sterno-thoracic CPR (SST-CPR) vs. standard CPR (S-CPR) using a mechanical resuscitator in a canine model of cardiac arrest. DEVICE DESCRIPTION: We have built a device that depresses the sternum and circumferentially constricts the thorax simultaneously. This device has two components. The first component is a piston, which depresses the sternum. The second is a circumferential strap that constricts the thorax as the piston is pushed down on the sternum. MATERIALS AND METHODS: Twelve domestic dogs were enrolled in this study. After catheterizations to measure pressures from the aorta and the right atrium, ventricular fibrillation was induced by passing AC current to the right ventricle. After 4 minutes of cardiac arrest, S-CPR and SST-CPR were performed alternatively. Aortic pressure, right atrial pressure, cardiac output, and end tidal CO2 were measured while each method of CPR was performing. RESULTS: SST-CPR resulted in significantly higher mean arterial pressure than S-CPR (68.9+/-16.1 vs 30.5+/-10.0 mmHg, p<0.01). SST-CPR could generate higher coronary perfusion pressure than S-CPR (47.0+/-11.4 vs 17.3+/-8.9 mmHg, p<0.01). End tidal CO2 tension was also higher during SST-CPR than S-CPR (11.6+/-6.1 vs 2.17+/-3.3 mmHg, p<0.01). CONCLUSION: Simultaneous sternothoracic cardiopulmonary resuscitation is a new method of cardiopulmonary resuscitation, which can generate better hemodynamic effects than standard cardiopulmonary resuscitation.