Intraoperative blood salvage (IBS) system aspirates waste blood from surgical wound site, purifies it by "cell-washing", and returns it to the same patient. We developed a new IBS device called membrane autotransfusion (MAT) which purifies the waste blood using a hollow fiber membrane filter instead of a centrifuge. Phase-I program involved in-vitro studies using bovine blood which established the operating characteristics of the MAT. Two animal studies were also completed in Phase-I which showed that the recovered blood cells (RBC, WBC, and platelets) retained their normal functions, and that the MAT procedure had no observable side effects. Phase-II program proposes to further evaluate the MAT in ten calves. The animal experiment is designed to simulate controlled bleeding in an open surgical wound site so that the MAT procedure could be applied to salvage the shed blood and reinfuse it to the animal. Interaction of other systems such as heart-lung bypass and oxygenators are eliminated in this procedure so that effects of only the MAT procedure on the animal could be determined. About 5 liters of blood will be processed in each experiment. Blood samples of the shed and the purified blood will be subjected to hematological and cell function tests. Health of the animal will be monitored for one week post-operation. This study is expected to establish the efficiency and the safety features of the MAT procedure.