Abstract
The objectives of this study were 1) to design completely implantable total artificial heart (TAH) and ventricular assist device (VAD) intended for 60Kg adults, and 2) to investigate the reliable, effective and physiologic control methods. The TAH is one-piece design with a miniature DC brush-less motor and planetary roller screw being sandwiched between the left and right pusher-plate type blood pumps. The TAH is operated lathe altemate ejection mode. The stroke volume is 60cc and nominal pump output is 4-5L/min with the maximum flow of 8l/min The blood contacting surfaces including pump housing, flexible diaphragm and inflow and outflow valves are made from polyurethane. The pump dimension is 90mm in diameter and 73mm in thickness. The pump volume is 440cc with weight bang 500g. The VAD is made using same components of the TAH and its volume and weight are 370cc and 560g, respectively. As the control methods, we investigated 1) Hall effect sensor based control, 2) invasive physiologic control and 3) noninvasive physiologic control. The TAN and VAD can run effectively and reliably with the Hall effect sensor based fill/empty operation. However, during exercise when oxygen consumption rapidly increases, the secondary control method may be necessary. The mixed venous oxygen saturation measured using reflectance optical sensor comes well with the oxygen oonsumption, allowing control of pump output. Thirdly, we looked into applications of noninvasive physiologic measurements such as ECG and blood pressure (BP) waveform to obtain status of the autonomic nervous systems (ANS). The results indicated that ANS status can be evaluated through noninvasive BP waveform analysis, which can be possibly used to control pump output of the completely implantable TAN and VAD
