Closed-loop real-time simulation model of hemodynamics and oxygen transport in the cardiovascular system

Abstract

BackgroundComputer technology enables realistic simulation of cardiovascular physiology. The increasing number of clinical surgical and medical treatment options imposes a need for better understanding of patient-specific pathology and outcome prediction.MethodsA distributed lumped parameter real-time closed-loop model with 26 vascular segments, cardiac modelling with time-varying elastance functions and gradually opening and closing valves, the pericardium, intrathoracic pressure, the atrial and ventricular septum, various pathological states and including oxygen transport has been developed.ResultsModel output is pressure, volume, flow and oxygen saturation from every cardiac and vascular compartment. The model produces relevant clinical output and validation of quantitative data in normal physiology and qualitative directions in simulation of pathological states show good agreement with published data.ConclusionThe results show that it is possible to build a clinically relevant real-time computer simulation model of the normal adult cardiovascular system. It is suggested that understanding qualitative interaction between physiological parameters in health and disease may be improved by using the model, although further model development and validation is needed for quantitative patient-specific outcome prediction.

Venous Cannula Positioning in Arterial Deoxygenation During Veno-Arterial Extracorporeal Membrane Oxygenation-A Simulation Study and Case Report

“…A closed‐loop real‐time simulation model was developed consisting of 27 vascular segments, the four cardiac chambers with corresponding valves, septal interactions, the pericardium and intrathoracic pressure (Fig. ) published elsewhere . The cardiac chambers are represented as time‐varying elastances and the closed‐loop vascular system segments characterized by nonlinear resistances, compliances, inertias and visco‐elastances.…”

A diagnostic, monitoring, and predictive tool for patients with complex valvular, vascular and ventricular diseases

“…To model the normalized elastance function of the LV, we tried three functions: (1) a summation of Gaussian functions 23,24 , (2) a Boltzmann Distribution 25 , and (3) a double Hill function 26,27 . We simulated the Table 1.…”

“…The Boltzmann distribution is a probability distribution of physical states 25 , and hence does not capture the dynamic cooperativity of myocytes recruitment. Consequently, to model the LV normalized time-varying elastance curves (E N ), we used a double Hill function as the following 26,27 : where N , τ 1 , τ 2 , m 1 , m 2 , and E min are elastane normalization, ascending time translation, descending time translation, ascending gradient, descending gradient, and minimum elastance, respectively (see Table 1). A double Hill function was deemed necessary to model the contraction and relaxation in the heart chambers: in Eq.…”

Modelling the heart with the atrioventricular plane as a piston unit

“…In contrast to empirical models in which the cardiac chambers are described as a flow/pressure source or as a time-varying elastance [34][35][36], this approach contributes to the understanding of underlying principles of cardiac pumping.…”

“…Even though there has been increased clinical interest in measuring longitudinal AV-plane motion over the last decades, AV interaction is usually ignored in cardiac-simulation models [25,26,[34][35][36]. The few previous models in which AV-plane displacement has been addressed treat this motion as a local phenomenon, considering equal atrial and ventricular cross-sections [23,24], or study the ways that AV-plane displacement is influenced by changes in boundary conditions [7].…”