A portable pneumatic driving unit for a left ventricular assist device

The authors developed a portable air driving unit for an artificial heart. As the portable energy source of the driver, a commercially available Ni-Cd battery was used. A linear compressor was selected as a portable size compressor. To reduce the number of parts to be assembled, a new type of pneumatic system was employed. In this system, the pressure level was regulated by varying the output flow rate of the compressor instead of using a pressure regulator and large air reservoirs. A one-board microcomputer and pressure sensors were used to control the pressure level. The total weight of the unit is 9.5 Kg. After assembling the components into the portable unit, a blood pump was connected to examine the output characteristics of the system. It was confirmed that the unit could drive the blood pump continuously for more than 2 hours under the following conditions: output flow rate of the blood pump = 5 L/min and output pressure = 100 mmHg.