References of "Dauby, Pierre"
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See detailA mathematical model of respiration under protective ventilation and extracorporeal CO2 removal therapy
Habran, Simon ULg; Desaive, Thomas ULg; MORIMONT, Philippe ULg 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 Comparison between four Techniques to Measure Cardiac Output
Pironet, Antoine ULg; Dauby, Pierre ULg; 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 ULg; Dauby, Pierre ULg; 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 ULg; Dauby, Pierre ULg; MORIMONT, Philippe ULg et al

Conference (2016, June 02)

Fluid resuscitation is the first choice therapy for sepctic shock. However, fluid infusion only increases cardiac output in approximately 50 % of cases, while an excess of fluid can have harmful effects ... [more ▼]

Fluid resuscitation is the first choice therapy for sepctic shock. However, fluid infusion only increases cardiac output in approximately 50 % of cases, while an excess of fluid can have harmful effects. Therefore, clinicians are looking for indices to predict the effect of fluid infusion on cardiac output, before giving fluid. In this work, a minimal mathematical model of the cardiovascular system is used, representing the heart, an artery and a vein. The nine model parameters, including total stressed blood volume, are identified from experimental data. The experimental data was recorded during three 500 ml fluid infusions on two pigs infected with endotoxin, to simulate septic shock. The total stressed blood volume parameter is negatively associated with the change in cardiac output after fluid infusion, as observed in previous studies. Subsequently, an algorithm is proposed to guide fluid resuscitation, based on the value of this parameter. The use of the algorithm results in 60 % less fluid being given with virtually no effect on cardiac output. The decision algorithm has the potential to be used in human clinical trials since the data required for parameter identification can be obtained in an intensive care unit. [less ▲]

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See detailHeart failure assessment with a multiscale model
Negroni, Jorge; Cabrera-Fischer, Edmundo; Kosta, Sarah ULg et al

Poster (2016, April 21)

Many cardiac diseases lead to heart failure (HF) causing increasing morbidity and mortality worldwide. Several alterations at the myocyte level have been identified, but their specific influence on ... [more ▼]

Many cardiac diseases lead to heart failure (HF) causing increasing morbidity and mortality worldwide. Several alterations at the myocyte level have been identified, but their specific influence on contractile and hemodynamic impairment is not yet clear. Mathematical modeling is a tool to address this issue enabling the analysis of individual myocyte changes on the overall circulatory response. Some myocyte models have been able to reproduce the impact of HF on experimentally detected myocyte components (1), but their integration into a ventricular model forming part of a multiscale circulatory approach has not been fully undertaken. Thus, the aim of this study is to compare the experimental hemodynamic and regional contractile response to acute HF versus a multiscale model based on a human myocyte representation. The experimentally-validated multiscale model shows adequate coupling between myocyte-derived left ventricular chamber and circulatory properties , and would be useful to predict the contractile and hemodynamic response to HF changes in myocyte variables. [less ▲]

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See detailParameter Correlation Analysis in Four Mathematical Models of Left Ventricular Relaxation
Pironet, Antoine ULg; MORIMONT, Philippe ULg; Dauby, Pierre ULg et al

in 14th Belgian Day on Biomedical Engineering (2016, March 04)

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See detailStructural identifiability analysis of a cardiovascular system model
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

in Medical engineering & physics (2016)

The six-chamber cardiovascular system model of Burkhoff and Tyberg has been used in several theoretical and experimental studies. However, this cardiovascular system model (and others derived from it) are ... [more ▼]

The six-chamber cardiovascular system model of Burkhoff and Tyberg has been used in several theoretical and experimental studies. However, this cardiovascular system model (and others derived from it) are not identifiable from any output set. In this work, two such cases of structural non-identifiability are first presented. These cases occur when the model output set only contains a single type of information (pressure or volume). A specific output set is thus chosen, mixing pressure and volume information and containing only a limited number of clinically available measurements. Then, by manipulating the model equations involving these outputs, it is demonstrated that the six-chamber cardiovascular system model is structurally globally identifiable. A further simplification is made, assuming known cardiac valve resistances. Because of the poor practical identifiability of these four parameters, this assumption is usual. Under this hypothesis, the six-chamber cardiovascular system model is structurally identifiable from an even smaller dataset. As a consequence, parameter values computed from limited but well-chosen datasets are theoretically unique. This means that the parameter identification procedure can safely be performed on the model from such a well-chosen dataset. Thus, the model may be considered suitable for use in diagnosis. [less ▲]

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See detailSize of cannula for extracorporeal CO2 removal therapies
Habran, Simon ULg; Desaive, Thomas ULg; MORIMONT, Philippe ULg et al

Conference (2015, November 26)

Extracorporeal CO2 removal devices (ECCO2R) can be used in clinics to decarboxylate blood externally for patients suffering from pulmonary insufficiencies like acute respiratory distress syndrome. In this ... [more ▼]

Extracorporeal CO2 removal devices (ECCO2R) can be used in clinics to decarboxylate blood externally for patients suffering from pulmonary insufficiencies like acute respiratory distress syndrome. In this work, we propose a model of the respiratory system coupled with such a device to analyze the decrease of CO2 partial pressure in the blood as a function of the blood flow through the device. Thanks to this information, the size of the cannulae can be optimized. [less ▲]

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See detailParameter Correlation Analysis in Four Mathematical Models of Left Ventricular Relaxation
Pironet, Antoine ULg; MORIMONT, Philippe ULg; Dauby, Pierre ULg et al

in Proceedings of the IEEE-EMBS Benelux chapter 2015 meeting (2015, November 26)

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See detailParameter Identification Methods in a Model of the Cardiovascular System
Pironet, Antoine ULg; Desaive, Thomas ULg; Dauby, Pierre ULg et al

Poster (2015, September 01)

To be clinically relevant, mathematical models have to be patient-specific, meaning that their parameters have to be identified from patient data. To achieve real time monitoring, it is important to ... [more ▼]

To be clinically relevant, mathematical models have to be patient-specific, meaning that their parameters have to be identified from patient data. To achieve real time monitoring, it is important to select the best parameter identification method, in terms of speed, efficiency and reliability. This work presents a comparison of seven parameter identification methods applied to a lumped-parameter cardiovascular system model. The seven methods are tested using in silico and experimental reference data. To do so, precise formulae for initial parameter values first had to be developed. The test results indicate that the trust-region reflective method seems to be the best method for the present model. This method (and the proportional method) are able to perform parameter identification in two to three minutes, and will thus benefit cardiac and vascular monitoring applications. [less ▲]

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See detailModel-Based Stressed Blood Volume is an Index of Fluid Responsiveness
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

Conference (2015, September 01)

Fluid therapy is frequently used to manage acute circulatory failure. This therapy aims to restore cardiac output by fluid administration, which increases the quantity of fluid in the circulation. However ... [more ▼]

Fluid therapy is frequently used to manage acute circulatory failure. This therapy aims to restore cardiac output by fluid administration, which increases the quantity of fluid in the circulation. However, it has been shown to be effective only in certain cases, leading to the need for indices of fluid responsiveness. Total stressed blood volume has recently been shown to be such an index of fluid responsiveness. However, the current methods to determine this parameter require specific procedures. In this work, a more straightforward method is developed using data available in the intensive care unit. A simple three-chamber cardiovascular system model is used, of which total stressed blood volume is a parameter. All model parameters (including total stressed blood volume) are adjusted to pig experimental data during fluid administrations. The resulting value of total stressed blood volume is always negatively associated with the relative change in cardiac output after fluid administration. This finding confirms that total stressed blood volume is an index of fluid responsiveness. Another finding of this study is that the response curves are subject-specific. The method developed in this work can be applied to humans, since the data required is typically available in an intensive care unit. [less ▲]

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See detailParameter Identification Methods in a Model of the Cardiovascular System
Pironet, Antoine ULg; Desaive, Thomas ULg; Dauby, Pierre ULg et al

in IFAC PapersOnLine (2015, September)

To be clinically relevant, mathematical models have to be patient-specific, meaning that their parameters have to be identified from patient data. To achieve real time monitoring, it is important to ... [more ▼]

To be clinically relevant, mathematical models have to be patient-specific, meaning that their parameters have to be identified from patient data. To achieve real time monitoring, it is important to select the best parameter identification method, in terms of speed, efficiency and reliability. This work presents a comparison of seven parameter identification methods applied to a lumped-parameter cardiovascular system model. The seven methods are tested using in silico and experimental reference data. To do so, precise formulae for initial parameter values first had to be developed. The test results indicate that the trust-region reflective method seems to be the best method for the present model. This method (and the proportional method) are able to perform parameter identification in two to three minutes, and will thus benefit cardiac and vascular monitoring applications. [less ▲]

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See detailModel-Based Stressed Blood Volume is an Index of Fluid Responsiveness
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

in IFAC PapersOnLine (2015, September)

Fluid therapy is frequently used to manage acute circulatory failure. This therapy aims to restore cardiac output by fluid administration, which increases the quantity of fluid in the circulation. However ... [more ▼]

Fluid therapy is frequently used to manage acute circulatory failure. This therapy aims to restore cardiac output by fluid administration, which increases the quantity of fluid in the circulation. However, it has been shown to be effective only in certain cases, leading to the need for indices of fluid responsiveness. Total stressed blood volume has recently been shown to be such an index of fluid responsiveness. However, the current methods to determine this parameter require specific procedures. In this work, a more straightforward method is developed using data available in the intensive care unit. A simple three-chamber cardiovascular system model is used, of which total stressed blood volume is a parameter. All model parameters (including total stressed blood volume) are adjusted to pig experimental data during fluid administrations. The resulting value of total stressed blood volume is always negatively associated with the relative change in cardiac output after fluid administration. This finding confirms that total stressed blood volume is an index of fluid responsiveness. Another finding of this study is that the response curves are subject-specific. The method developed in this work can be applied to humans, since the data required is typically available in an intensive care unit. [less ▲]

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See detailCell-based description of ventricular contraction in a model of the human cardiovascular system
Kosta, Sarah ULg; Negroni, Jorge; Lascano, Elena et al

in Preprints of the 9th IFAC Symposium on Biological and Medical Systems (2015, September)

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

A multiscale model of the cardiovascular system (CVS) 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 extremal values of the sarcomere length, which must keep physiological values. This model is able to reproduce healthy behavior, preload variations experiments, and ventricular failure. [less ▲]

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See detailCell-based description of ventricular contraction in a model of the human cardiovascular system
Kosta, Sarah ULg; Negroni, Jorge; Lascano, Elena et al

Poster (2015, August 31)

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See detailMathematical modeling of extracorporeal CO2 removal
Habran, Simon ULg; Dauby, Pierre ULg; Desaive, Thomas ULg et al

Poster (2015, August)

Extra¬cor¬poreal CO2 removal devices (ECCO2R) can be used in clinics to decarboxylate blood externally for patients suffering from pulmonary insufficiencies like acute respiratory distress syndrome. In ... [more ▼]

Extra¬cor¬poreal CO2 removal devices (ECCO2R) can be used in clinics to decarboxylate blood externally for patients suffering from pulmonary insufficiencies like acute respiratory distress syndrome. In this work, a model of the respiratory system coupled with such a device is proposed to analyze the decrease of CO2 partial pressure in blood as a function of blood flow through the device. This model provides a mathematical tool which could help clinicians to choose the optimal settings of ECCO2R. [less ▲]

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See detailModel-based computation of total stressed blood volume from a preload reduction manoeuvre
Pironet, Antoine ULg; Desaive, Thomas ULg; Chase, J. Geoffrey et al

in Mathematical Biosciences (2015), 265(0), 28-39

Total stressed blood volume is an important parameter for both doctors and engineers. From a medical point of view, it has been associated with the success or failure of fluid therapy, a primary treatment ... [more ▼]

Total stressed blood volume is an important parameter for both doctors and engineers. From a medical point of view, it has been associated with the success or failure of fluid therapy, a primary treatment to manage acute circulatory failure. From an engineering point of view, it dictates the cardiovascular system’s behavior in changing physiological situations. Current methods to determine this parameter involve repeated phases of circulatory arrests followed by fluid administration. In this work, a more straightforward method is developed using data from a preload reduction manoeuvre. A simple six-chamber cardiovascular system model is used and its parameters are adjusted to pig experimental data. The parameter adjustment process has three steps: (1) compute nominal values for all model parameters; (2) determine the five most sensitive parameters; and (3) adjust only these five parameters. Stressed blood volume was selected by the algorithm, which emphasizes the importance of this parameter. The model was able to track experimental trends with a maximal root mean squared error of 29.2%. Computed stressed blood volume equals 486 ± 117 ml or 15.7 ± 3.6 ml/kg, which matches previous independent experiments on pigs, dogs and humans. The method proposed in this work thus provides a simple way to compute total stressed blood volume from usual hemodynamic data. [less ▲]

Detailed reference viewed: 29 (8 ULg)