벨로우즈 방식의 폐회로를 가진 공압식 심실 보조장치의 최적 작동을 위한 압력 조절 시스템

초록

Ventricular Assist Device(VAD) hasswitched its goal from a short-term use for bridge-to-transplantation to a long-term use for destination therapy. With this goal, the importance of long-term reliability gets more interests and importances. H-VAD is an portable extracorporeal biventricular assist device, and adopts an electro-pneumatic drivingmechanism. The pneumatic pressure to pump out blood is generated with compression of bellows, and istransmitted in a closed pneumatic circuit through a pneumatic line. The existing pneumatic VAD adopts a air compressor which can generate stable pressures but has defects such as a noise and a size problem. Thus, it is not suitable for being used as a portable device. These problems are covered with adopting a closed pneumatic circuit mechanismwith a bellows which has a smallsize and small noise generation, but it has defects that improper pneumatic setting causes a failure of adequate flow generation. In this study, the pneumatic pressure regulation system is developed to cover these defects of a bellows-type pneumatic VAD. The optimal pneumatic pressure conditions according to various afterload conditions for an optimal flow rate were investigated and the afterload estimation algorithm was developed. The final pneumatic regulation system estimates a current afterload and regulate the pneumatic pressure to the optimal point at a given afterload condition. The afterload estimation algorithm showed a sufficient performance that the standard deviation of error is 8.8 mmHg. The pneumatic pressure regulation system showed a sufficient performance that the flow rate was stably governed to various afterload conditions. In a furtherstudy, if a additionalsensorsuch as ultrasonic sensor is developed to monitor the direct movement of diaphragm in a blood pump part, the reliability would be greatly increased. Moreover, if the afterload estimation algorithm gets more accuracy, it would be also helpful to monitor the hemodynamic condition of patients

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