Singapore: World Scientific Publishing Co. Pte. Ltd.
The Phoenix 7 total artificial heart was studied in order to obtain detailed information of its flow pattern. Both the left and right sides of the heart were mounted in a mock circulation loop system. Flow visualization and a 2-D laser Doppler anemometer were used to observe the flow field. There was a good agreement between the quantitative results and visualization results. Equipped with a novel triangular-shaped diaphragm, driven by pneumatics, the Phoenix 7 could fully induce the fluid into and expel it from the inner cavity, without any stagnation. This also provided the inner walls with a good wash-out effect, thus reducing the chances of blood aggregation and the occurrence of thromboembolism. The turbulence Reynolds shear stress was greater near the valves than inside the cavity. The peak principal Reynolds shear stress at the valves equaled 772 dyn/cm 2 in the left heart and 460 dyn/cm 2 in the right heart. Although these amounts of stress do not exceed the 1500 dyn/cm 2 limit of hemolysis, they can still cause platelet damage, which occurs at 100-500 dyn/cm 2. However, when the turbulence length scales and exposure time are considered, the damage caused the platelets is insignificant.
Biomedical Engineering: Applications, Basis and Communications 11(5), pp.277-284