Right ventricular assistance by continuous flow device. A numerical simulation.
OBJECTIVE
This work is another step in the development of the circulatory model CARDIOSIM and of its model library. Continuous flow assistance is often used to support the right ventricular failure. Computer simulation is one of the methods to study the effect of this assistance on the failing ventricle. The purpose of this study was to evaluate the effect of this support on some hemodynamic variables, when different right ventricular end-systolic elastance and pump speed values were applied.


METHODS
The rotary blood pump model was included into the software package CARDIOSIM, which reproduces the cardiovascular system. Lumped parameters models were used to reproduce the circulatory phenomena. Variable elastance models reproduced the Starling's law of the heart for both ventricles. In the study right ventricular end-systolic elastance (EmaxRIGHT) and the rotational speed of the pump took three different values. All the other parameters of the model were constants.


RESULTS
The rotational speed of the pump had a significant influence on right ventricular end-diastolic and end-systolic volumes, right atrial pressure (Pra), right ventricular (Qro) and pump flows. The effects on pulmonary arterial pressure (Pap) were more evident when the right ventricular end-systolic elastance was low. When the speed of the device increased the mean value of Pra decreased for each value of EmaxRIGHT. The total flow (Qro+pump flow) increased when the speed of the pump increased.


CONCLUSIONS
Our simulation (in good agreement with the results presented in literature) showed that Hemopump produces a rise in total flow, a drop in blood flow pumped out by the right ventricle and a drop in right atrial pressure.
De Lazzari
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C.N.R., Institute of Clinical Physiology-Rome Section-Italy, Group of Cardiovascular Engineering, V.le dell'Università, 11, 00185 Rome, Italy. dela@ifc.cnr.it
Ferrari
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D001794:Blood Pressure; D002320:Cardiovascular Physiological Phenomena; D002319:Cardiovascular System; D003198:Computer Simulation; D003971:Diastole / Q000502:physiology; D006339:Heart Rate; D006352:Heart Ventricles; D006353:Heart-Assist Devices; D006801:Humans; D008962:Models, Theoretical; D012984:Software; D013599:Systole / Q000502:physiology