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Full-Text Articles in Engineering

An Algorithm For Coupling Multibranch In Vitro Experiment To Numerical Physiology Simulation For A Hybrid Cardiovascular Model, Ehsan Mirzaei, Masoud Farahmand, Ethan Kung Dec 2019

An Algorithm For Coupling Multibranch In Vitro Experiment To Numerical Physiology Simulation For A Hybrid Cardiovascular Model, Ehsan Mirzaei, Masoud Farahmand, Ethan Kung

Publications

The hybrid cardiovascular modeling approach integrates an in vitro experiment with a computational lumped‐parameter simulation, enabling direct physical testing of medical devices in the context of closed‐loop physiology. The interface between the in vitro and computational domains is essential for properly capturing the dynamic interactions of the two. To this end, we developed an iterative algorithm capable of coupling an in vitro experiment containing multiple branches to a lumped‐parameter physiology simulation. This algorithm identifies the unique flow waveform solution for each branch of the experiment using an iterative Broyden's approach. For the purpose of algorithm testing, we first used mathematical …


Factors Affecting Cardiovascular Physiology In Cardiothoracic Surgery: Implications For Lumped-Parameter Modeling, Joshua Kaufmann, Ethan Kung Nov 2019

Factors Affecting Cardiovascular Physiology In Cardiothoracic Surgery: Implications For Lumped-Parameter Modeling, Joshua Kaufmann, Ethan Kung

Publications

Cardiothoracic surgeries are complex procedures during which the patient cardiovascular physiology is constantly changing due to various factors. Physiological changes begin with the induction of anesthesia, whose effects remain active into the postoperative period. Depending on the surgery, patients may require the use of cardiopulmonary bypass and cardioplegia, both of which affect postoperative physiology such as cardiac index and vascular resistance. Complications may arise due to adverse reactions to the surgery, causing hemodynamic instability. In response, fluid resuscitation and/or vasoactive agents with varying effects may be used in the intraoperative or postoperative periods to improve patient hemodynamics. These factors have …


A Hybrid Experimental‐Computational Modeling Framework For Cardiovascular Device Testing, Ethan Kung, Masoud Farahmand, Akash Gupta Mar 2019

A Hybrid Experimental‐Computational Modeling Framework For Cardiovascular Device Testing, Ethan Kung, Masoud Farahmand, Akash Gupta

Publications

Significant advances in biomedical science often leverage powerful computational and experimental modeling platforms. We present a framework named physiology simulation coupled experiment (“PSCOPE”) that can capitalize on the strengths of both types of platforms in a single hybrid model. PSCOPE uses an iterative method to couple an in vitro mock circuit to a lumped-parameter numerical simulation of physiology, obtaining closed-loop feedback between the two. We first compared the results of Fontan graft obstruction scenarios modeled using both PSCOPE and an established multiscale computational fluid dynamics method; the normalized root-mean-square error values of important physiologic parameters were between 0.1% and 2.1%, …