VDR (volumetric diffusive respiration) is the newest high-frequency ventilation technique that combines conventional mechanical ventilation (CMV) and IPV (intrapulmonary percussive ventilation), and is also called HFPV (high-frequency percussive ventilation). To evaluate the effects of VDR on cardiopulmonary hemodynamics and oxygenation, we compared VDR with CMV in 8 mongrel dogs. In both groups, ventilation and oxygenation were well maintained and we couldnt find any differences between groups. Hemodynamically there were no significant differences, but diastolic arterial pressure, pulmonary capillary wedge pressure, coronary perfusion pressure, and both right and left ventricular stroke work index were slightly increased. These results suggest that VDR maintains cardiovascular stability, good ventilation and oxygenation, and there are no differences, compared with CMV, in dogs with normal lung.