To determine the efficacy of high-volume, high-pressure pulsatile lavage in the prevention of cardiopulmonary dysfunction and fat embolism during cemented arthroplasty, we studied twenty-eight mongrel dogs that had had a bilateral cemented arthroplasty. Significant increases in pulmonary-artery pressure and pulmonary vascular resistance, accompanied by decreases in arterial oxygen tension and increases in intrapulmonary shunt fraction (Qs/Qt), characterized cardiopulmonary dysfunction after bilateral cemented arthroplasty when no lavage was used. Low-volume, low-pressure manual lavage did not significantly alter these physiological changes, but there was a significant reduction in the number of fat emboli that were demonstrated in the lungs as compared with the no-lavage group. High-volume, high-pressure pulsatile lavage of the intramedullary cavity after reaming significantly reduced the changes in pulmonary-artery pressure, pulmonary vascular resistance, arterial oxygen tension, and intrapulmonary shunt fraction (Qs/Qt). In the pulsatile-lavage group, the number of fat microemboli that were found in the lungs was reduced to 25.7 per cent of those found in the no-lavage group. We concluded that meticulous high-volume, high-pressure pulsatile lavage reduces both pulmonary physiological derangements and fat emboli during bilateral cemented arthroplasty in dogs.