| Co-Investigator(Kenkyū-buntansha) |
MASUZAWA Toru National Cardiovascular Center Research Institute, Department of Artificial Orga, 人工臓器部, 室長 (40199691)
NAKATANI Takeshi National Cardiovascular Center Research Institute, Department of Biomedical Engi, 生体工学部, 室長 (60155752)
TAENAKA Yoshiyuki National Cardiovascular Center Research Institute, Department of Artificial Orga, 人工臓器部, 部長 (00142183)
TAKANO Hisateru National Cardiovascular Center Research Institute, Deputy Director of the Resear, 副所長 (60028595)
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| Research Abstract |
An electrohydraulic total artificial heart (EHTAH) system is has been developed. The system comprises of diaphragm-type ellipsoidal blood pumps and an electrohydraulic actuator consisting of a regenerative pumprushless DC motor assembly, and an electronics system with transcutaneous energy transfer (TET) and optical telemetry (TOT) systems. Excellent anatomic fit of the pumping unit to the human chest cavity was confirmed by computer graphics based on magnetic resonance imaging. The energy converter, reciprocating hydraulic oil to alternate blood pumps through flexible conduits, is to be placed in the abdominal region for minimizing anatomic constraints. In this 2nd iteration pumping unit, the maximum output was over 10 L/min, and the energy consumptin and energy efficiency were around 10 W and 12% at 5L/min output, respectively. The pumping unit was implanted in a 62 kg calf, and was successfully actuated by an external controller for 10days. During the experiment, the animal's circul
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ation was stably maintained by the EHTAH with an adequate left-right balance. Generation and dissipation of heat from the device was also acceptable. There occurred, however, several mechanical failures including bearing breakdown resulting in device malfunction. The device demonstrated good anatomic fit at autopsy without compromising the great vessels and adjacent tissues. Thus, the EHTAH pumping unit was proved to have a sufficient in vivo basic performance, although appropriate measures are to be implemented aginst the mechanical problems detected. The TET and TOT systems were evaluated in chronic animal studies. The TET system consisting of a pair of annular coils demonstrated around 80% of DC/DC efficiency over 40 days when 20 watts of energy was finally transferred into a simulated load. The TOT system at 19,200 bps of signal transmission rate allowed up to 12 mm of misalignment. Based on these favorable results, the 3rd iteration system is being developed to acquire longer durability and higher reliability. Less
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