References of "Dauby, Pierre"
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See detailExtracorporeal CO2 removal and regional citrate anticoagulation in an experimental model of hypercapnic acidosis.
Morimont, Philippe ULiege; Habran, Simon; Desaive, Thomas ULiege et al

in Artificial Organs (2019)

Low flow extracorporeal veno-venous CO2 removal (ECCO2 R) therapy is used to remove CO2 while reducing ventilation intensity. However, the use of this technique is limited because efficiency of CO2 ... [more ▼]

Low flow extracorporeal veno-venous CO2 removal (ECCO2 R) therapy is used to remove CO2 while reducing ventilation intensity. However, the use of this technique is limited because efficiency of CO2 removal and potential beneficial effects on pulmonary hemodynamics are not precisely established. Moreover, this technique requires anticoagulation that may induce severe complications in critically ill patients. This study aimed at determining precisely efficiency of CO2 extraction and its effects on right ventricular (RV) afterload, and comparing regional anticoagulation with citrate to systemic heparin anticoagulation during ECCO2 R. ECCO2 R was highly efficient to normalize pH and PaCO2 and to reduce RV afterload resulting from hypercapnic acidosis. Regional anticoagulation with citrate solution was as effective as standard heparin anticoagulation but did not improve CO2 removal and lead to more hypocalcemia and hypotension. [less ▲]

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See detailAfterload burden on the right ventricle is enhanced when ARDS is associated with hypercapnic acidosis.
MORIMONT, Philippe ULiege; Habran, Simon ULiege; Desaive, Thomas ULiege et al

in Annals of Intensive Care (2018, February 05), 8(1),

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See detailSelf-assembly of carbon nanotube-based composites by means of evaporation-assisted depositions: importance of drop-by-drop self-assembly on material properties
Machrafi, Hatim ULiege; Minetti, Christophe; Miskovic, Vanja et al

in Materials Chemistry and Physics (2018)

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See detailExperimental assessment of a myocyte-based multiscale model of cardiac contractile dysfunction.
Lascano, Elena C.; Felice, Juan I.; Wray, Sandra et al

in Journal of Theoretical Biology (2018), 456

Cardiac contractile dysfunction (CD) is a multifactorial syndrome caused by different acute or progressive diseases which hamper assessing the role of the underlying mechanisms characterizing a defined ... [more ▼]

Cardiac contractile dysfunction (CD) is a multifactorial syndrome caused by different acute or progressive diseases which hamper assessing the role of the underlying mechanisms characterizing a defined pathological condition. Mathematical modeling can help to understand the processes involved in CD and analyze their relative impact in the overall response. The aim of this study was thus to use a myocyte-based multiscale model of the circulatory system to simulate the effects of halothane, a volatile anesthetic which at high doses elicits significant acute CD both in isolated myocytes and intact animals. Ventricular chambers built using a human myocyte model were incorporated into a whole circulatory system represented by resistances and capacitances. Halothane-induced decreased sarco(endo)plasmic reticulum Ca(2+) (SERCA2a) reuptake pump, transient outward K(+) (Ito), Na(+)-Ca(2+) exchanger (INCX) and L-type Ca(2+) channel (ICaL) currents, together with ryanodine receptor (RyR2) increased open probability (Po) and reduced myofilament Ca(2+) sensitivity, reproduced equivalent decreased action potential duration at 90% repolarization and intracellular Ca(2+) concentration at the myocyte level reported in the literature. In the whole circulatory system, model reduction in mean arterial pressure, cardiac output and regional wall thickening fraction was similar to experimental results in open-chest sheep subjected to acute halothane overdose. Effective model performance indicates that the model structure could be used to study other changes in myocyte targets eliciting CD. [less ▲]

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See detailEffect of including a gas layer on the gel formation process during the drying of a polymer solution
Rabani, Ramin ULiege; Machrafi, Hatim ULiege; Dauby, Pierre ULiege

in The European Physical Journal E (2017), 40(89), 11579-3

In this paper, we study the influence of the upper gas layer on the drying and gelation of a polymer solution. The gel is formed due to the evaporation of the binary solution into (inert) air. A one ... [more ▼]

In this paper, we study the influence of the upper gas layer on the drying and gelation of a polymer solution. The gel is formed due to the evaporation of the binary solution into (inert) air. A one dimensional model is proposed, where the evaporation flux is more realistically described than in previous studies. The approach is based on general thermodynamic principles. A composition-dependent diffusion coefficient is used in the liquid phase and the local equilibrium hypothesis is introduced at the interface to describe the evaporation process. The results show that the high thickness of the gas layer reduces evaporation, thus leading to longer drying times. Our model is also compared with more phenomenological descriptions of evaporation, for which the mass flux through the interface is described by the introduction of a Peclet number. A global agreement is found for appropriate values of the Peclet numbers and our model can thus be considered as a tool allowing to link the value of the empirical Peclet number to the physics of the gas phase. Finally, in contrast with other models, our approach emphasizes the possibility of very fast gelation at the interface, which could prevent all Marangoni convection during the drying process. [less ▲]

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See detailA mathematical model of respiration under protective ventilation and extracorporeal CO2 removal therapy
Habran, Simon ULiege; Desaive, Thomas ULiege; MORIMONT, Philippe ULiege et al

Conference (2017, September 27)

The aim of the present study is to build a mathematical model of the respiratory system connected to an extracorporeal CO2 removal device (ECCO2RD) to optimize the gas exchanges efficiency. The model must ... [more ▼]

The aim of the present study is to build a mathematical model of the respiratory system connected to an extracorporeal CO2 removal device (ECCO2RD) to optimize the gas exchanges efficiency. The model must be simple enough to provide rapid solutions and to estimate specific parameters from available clinical data. But it also must be complex enough to be able to simulate the respiratory system when protective ventilation is used and when this system is assisted by an ECCO2RD. [less ▲]

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See detailA multiscale model of the human cardiovascular system can account for the Frank-Starling effect on vascular filling therapy
Kosta, Sarah ULiege; Pironet, Antoine; Negroni, Jorge et al

Poster (2017, February 01)

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See detailMultiscale model of the human cardiovascular system: Description of heart failure and comparison of contractility indices
Kosta, Sarah ULiege; Negroni, Jorge; Lascano, Elena et al

in Mathematical Biosciences (2017), 284

A multiscale model of the cardiovascular system is presented. Hemodynamics is described by a lumped parameter model, while heart contraction is described at the cellular scale. An electrophysiological ... [more ▼]

A multiscale model of the cardiovascular system is presented. Hemodynamics is described by a lumped parameter model, while heart contraction is described at the cellular scale. An electrophysiological model and a mechanical model were coupled and adjusted so that the pressure and volume of both ventricles are linked to the force and length of a half-sarcomere. Particular attention was paid to the extreme values of the sarcomere length, which must keep physiological values. This model is able to reproduce healthy behavior, preload variations experiments, and ventricular failure. It also allows to compare the relevance of standard cardiac contractility indices. This study shows that the theoretical gold standard for assessing cardiac contractility, namely the end-systolic elastance, is actually load-dependent and therefore not a reliable index of cardiac contractility. [less ▲]

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See detailSelf-assembly by multi-drop evaporation of carbon-nanotube droplets on a polycarbonate substrate
Machrafi, Hatim ULiege; Minetti, C.; Dauby, Pierre ULiege et al

in Physica E: Low-Dimensional Systems and Nanostructures (2017), 85

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See detailTemperature, geometry, and bifurcations in the numerical modeling of the cardiac mechano-electric feedback.
Collet, A.; Bragard, J.; Dauby, Pierre ULiege

in Chaos (Woodbury, N.Y.) (2017), 27(9), 093924

This article characterizes the cardiac autonomous electrical activity induced by the mechanical deformations in the cardiac tissue through the mechano-electric feedback. A simplified and qualitative model ... [more ▼]

This article characterizes the cardiac autonomous electrical activity induced by the mechanical deformations in the cardiac tissue through the mechano-electric feedback. A simplified and qualitative model is used to describe the system and we also account for temperature effects. The analysis emphasizes a very rich dynamics for the system, with periodic solutions, alternans, chaotic behaviors, etc. The possibility of self-sustained oscillations is analyzed in detail, particularly in terms of the values of important parameters such as the dimension of the system and the importance of the stretch-activated currents. It is also shown that high temperatures notably increase the parameter ranges for which self-sustained oscillations are observed and that several attractors can appear, depending on the location of the initial excitation of the system. Finally, the instability mechanisms by which the periodic solutions are destabilized have been studied by a Floquet analysis, which has revealed period-doubling phenomena and transient intermittencies. [less ▲]

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See detailPractical identifiability analysis of a minimal cardiovascular system model.
Pironet, Antoine; Docherty, Paul D.; Dauby, Pierre ULiege et al

in Computer Methods and Programs in Biomedicine (2017)

BACKGROUND AND OBJECTIVE: Parameters of mathematical models of the cardiovascular system can be used to monitor cardiovascular state, such as total stressed blood volume status, vessel elastance and ... [more ▼]

BACKGROUND AND OBJECTIVE: Parameters of mathematical models of the cardiovascular system can be used to monitor cardiovascular state, such as total stressed blood volume status, vessel elastance and resistance. To do so, the model parameters have to be estimated from data collected at the patient's bedside. This work considers a seven-parameter model of the cardiovascular system and investigates whether these parameters can be uniquely determined using indices derived from measurements of arterial and venous pressures, and stroke volume. METHODS: An error vector defined the residuals between the simulated and reference values of the seven clinically available haemodynamic indices. The sensitivity of this error vector to each model parameter was analysed, as well as the collinearity between parameters. To assess practical identifiability of the model parameters, profile-likelihood curves were constructed for each parameter. RESULTS: Four of the seven model parameters were found to be practically identifiable from the selected data. The remaining three parameters were practically non-identifiable. Among these non-identifiable parameters, one could be decreased as much as possible. The other two non-identifiable parameters were inversely correlated, which prevented their precise estimation. CONCLUSIONS: This work presented the practical identifiability analysis of a seven-parameter cardiovascular system model, from limited clinical data. The analysis showed that three of the seven parameters were practically non-identifiable, thus limiting the use of the model as a monitoring tool. Slight changes in the time-varying function modeling cardiac contraction and use of larger values for the reference range of venous pressure made the model fully practically identifiable. [less ▲]

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See detailEffect of citrate anticoagulation on CO2 extraction during low flow extracorporeal veno-venous CO2 removal therapy
MORIMONT, Philippe ULiege; Habran, Simon ULiege; Hubert, Romain et al

in Intensive Care Medicine Experimental (2016), 4

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See detailA Comparison between four Techniques to Measure Cardiac Output
Pironet, Antoine ULiege; Dauby, Pierre ULiege; Chase, J. Geoffrey et al

in Proceedings of the 38th International Conference of the IEEE Engineering in Medicine and Biology Society (2016, August 17)

Cardiac output is an important variable when monitoring hemodynamic status. In particular, changes in cardiac output represent the goal of several circulatory management therapies. Unfortunately, cardiac ... [more ▼]

Cardiac output is an important variable when monitoring hemodynamic status. In particular, changes in cardiac output represent the goal of several circulatory management therapies. Unfortunately, cardiac output is very difficult to estimate, either in experimental or clinical settings. The goal of this work is to compare four techniques to measure cardiac output: pressure-volume catheter, aortic flow probe, thermodilution, and the PiCCO monitor. These four techniques were simultaneously used during experiments of fluid and endotoxin administration on 7 pigs. Findings show that, first, each individual technique is precise, with a relative coefficient of repeatability lower than 7 %. Second, 1 cardiac output estimate provided by any technique relates poorly to the estimates from the other 3, even if there is only small bias between the techniques. Third, changes in cardiac output detected by one technique are only detected by the others in 62 to 100 % of cases. This study confirms the difficulty of obtaining a reliable clinical cardiac output measurement. Therefore, several measurements using different techniques should be performed, if possible, and all such should be treated with caution. [less ▲]

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See detailA Comparison between four Techniques to Measure Cardiac Output
Pironet, Antoine ULiege; Dauby, Pierre ULiege; Chase, J. Geoffrey et al

Poster (2016, August 17)

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See detailModel-Based Decision Support Algorithm to Guide Fluid Resuscitation
Pironet, Antoine ULiege; Dauby, Pierre ULiege; MORIMONT, Philippe ULiege et al

in IFAC-PapersOnLine (2016, July 26), 49(5), 224-229

Detailed reference viewed: 30 (7 ULiège)