Wave Intensity Analysis of Counter-Pulsation Circulation Support

• Main Authors: Bo-Wen Lin, 林博文
• Other Authors: Pong-Jeu Lu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/74216766790236878257

碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 95 === The present research aims at developing a system dynamic model that can simulate various hemodynamic and wave characteristics associated with the counter-pulsation circulation support. A novel hybrid circulation model consisting of a one-dimensional flow model and a lumped parameter circulation model was constructed. Wave propagation phenomenon in the arteries is simulated using the one-dimensional flow model with other parts of the vasculature represented by the lumped parameter circulation model. Roe-splitting upwind scheme was developed for this one-dimensional vascular equations and Runge-Kutta marching was used for time-stepping this coupled hybrid circulation system. Suga-Sagawa pressure-volume relationship was adopted to describe the time-varying left and right ventricular function. By adjusting the time-varying elastance of the ventricles, the healthy and failed heart conditions can be simulated. Failing heart supported either by intra-aortic balloon pump (IABP) or by para-aortic balloon pump (PABP) was simulated. These simulation results indicate that increasing pumping volume may result in left ventricular afterload reduction and cardiac output enhancement. For 40 ml pumping support, cardiac output was elevated to 4% and 11% for IABP and PABP, respectively. Moreover, contrary to the IABP support characteristics, heart rate does not show strong influence on PABP perfusion augmentation. Endocardical viability ratio (EVR), however, shows similar trend for both counter-pulsation devices. Using the wave intensity analysis, it was observed that, first, for diastolic augmentation, PABP produces stronger compression wave than does IABP; and second, left ventricle may generate steeper forward-going compression pressure waveform when assisted by PABP systolic unloading. The present wave intensity analysis (WIA) approach shows that counter-pulsation supported by PABP is more effective than that of the IABP.