Regional blood flow in the liver, pancreas and kidney was measured under conditions of profound hypothermia associated with total circulatory arrest, to determine whether cardiopulmonary bypass with pulsatile flow would improve the blood flow in these visceral organs in comparison with nonpulsatile flow. Using 56 adult mongrel dogs, total cardiopulmonary bypass was carried out to induce hypothermia and 40 min of total circulatory arrest was performed at 20 degrees C. After total arrest, the temperature was raised to 35 degrees C. With pulsatile flow, a decrease of the regional blood flow in the liver, pancreas and kidney was prevented during cooling, especially at 20 degrees C before total circulatory arrest. Moreover, regional renal blood flow recovered rapidly with pulsatile flow after total arrest at 20 degrees C, while after arrest with nonpulsatile flow blood flow in the kidney could not be measured in the cortex and was significantly lower in the medulla. In summary, pulsatile flow improves the hepatic, pancreatic and renal blood flow and, referring to our previous experiments, protects the function of these organs during cardiopulmonary bypass associated with profound hypothermia and total circulatory arrest.