title: Development of a thermodynamic control system for the Fontan circulation pulsation device using shape memory alloy fibers.
abstract: The Fontan procedure is one of the common surgical treatments for circulatory reconstruction in pediatric patients with congenital heart disease. In Fontan circulation, low pulsatility may induce localized lung ischemia and may impair the development of pulmonary peripheral endothelial cells. To promote pulmonary circulation in Fontan circulation, we have been developing a pediatric pulmonary circulatory pulsation device using shape memory alloy fibers attached from the outside of total cavopulmonary connection. In this study, we developed a new thermal control system for the device and examined its functions. We mounted on the device 16 fibers connected in parallel around an ePTFE graft circumferentially. To provide optimized contraction, we designed the new thermal control system. The system consisted of a thermistor, a pressure sensor, and a regulator that was controlled by the adaptive thermodynamic transfer functions. We monitored the parameters and calculated heat transfer function as well as pressure distribution on the graft surface. Then we examined and compared the dynamic contractile pressure and changes in surface temperature. As a result, by the application of the control based on the new feedback system analysis, the circumferential contractile pressure increased by 35%. The adaptive thermodynamic regulation was useful for the selection of alternative thresholds of the surface temperature of the graft. The system could achieve effective contraction for the pulsatile flow generation by the device.
authors.affiliation: Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan, akiyamada@idac.tohoku.ac.jp.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yamada
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Shiraishi
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Miura
authors.forename: Hashem Mohamed Omran
authors.initials: HM
authors.lastname: Hashem
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tsuboko
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yamagishi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yambe
mesh_terms: D000497:Alloys; D001243:Assisted Circulation / Q000295:instrumentation*; D002675:Child, Preschool; D004867:Equipment Design; D018729:Fontan Procedure / Q000295:instrumentation*; D006330:Heart Defects, Congenital / Q000601:surgery*; D006801:Humans; D011138:Polytetrafluoroethylene; D011651:Pulmonary Artery; D011652:Pulmonary Circulation / Q000502:physiology; D011673:Pulsatile Flow / Q000502:physiology; D013816:Thermodynamics; D014682:Vena Cava, Inferior
chemical_list: D000497:Alloys; D011138:Polytetrafluoroethylene