Linear bloodpump – a new concept for fluid propagation in cardiac assist devices or total artificial heart

Body: Long-term cardiac support and total artificial heart with displacement or rotary blood pumps is still crucial due to blood cell damage, hemolysis, thrombus formation or bleeding. We propose a new concept that is not in need of membranes for displacement or impellers for rotating motion of the fluid, but aims to mimic the displacement of an inlet valve against an outlet valve in the natural cardiac cycle. At the end of a tube (diameter 4cm, length 12cm) an outlet valve is fixed and a second valve moves within the tube against this valve, driven by a magnetic linear motor (see Figure 1). We build a model of a non-contact feed back regulated circumferential linear motor. In this setting mean energy loss is calculated to approximately 3 W at a flow rate of 4.8 l/min against a load of 120mm/Hg. Maximum force reaches 200mm Hg. As the gap between inner wall of the tube with carbon surface and the moving piston can be reduced to at least 5 mikrometer a laminar flow of low viscosity results. The blood pump can be designed for high frequencies and low displacement volumes making cardiac assist for new-borns and infants feasible.

Fig. 1