References of "Desaive, Thomas"
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See detailMitral valve dynamics in a closed-loop model of the cardiovascular system
Paeme, Sabine ULg; Chase, J. Geoffrey; Hann, christopher et al

in Archives des Maladies du Coeur et des Vaisseaux. Pratique (2009, December), hors série 1

A cardiovascular and circulatory system (CVS) model has been validated in silico, and in several animal model studies. It accounts for valve dynamics by means of Heaviside function to simulate “open on ... [more ▼]

A cardiovascular and circulatory system (CVS) model has been validated in silico, and in several animal model studies. It accounts for valve dynamics by means of Heaviside function to simulate “open on pressure, close on flow” law. Thus, it does not consider the real time scale of the valve aperture and thus doesn’t fully capture valve dysfunction. This work describes a new coupled model of the cardiovascular system that accounts for progressive mitral valve aperture. Simulations show good correlation with physiologically expected results for healthy or diseased valves. The large number of valve model parameters indicates a need for emerging, lighter and minimal mitral valve models that are readily identifiable to achieve full benefit in real-time use. These results suggest a further use of this model to track, diagnose and control valves pathologies. [less ▲]

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See detailUnique parameter identification of a cardiovascular system model using feedback control
Hann, C. E.; Chase, J. G.; Desaive, Thomas ULg et al

in Proc. 7th Intl Conf on Control and Automation (ICCA09) (2009, December)

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See detailUnique parameter identification for model-based cardiac diagnosis in critical care
Hann, C. E.; Chase, J. G.; Desaive, Thomas ULg et al

in IFAC Proceedings Volumes (IFAC-PapersOnline) (2009), 7(PART 1), 169-174

Lumped parameter approaches for modeling the cardiovascular system typically have many parameters of which many are not identifiable. The conventional approach is to only identify a small subset of ... [more ▼]

Lumped parameter approaches for modeling the cardiovascular system typically have many parameters of which many are not identifiable. The conventional approach is to only identify a small subset of parameters to match measured data, and to set the remaining parameters at population values. These values are often based on animal data or the "average human" response. The problem, is that setting many parameters at nominal fixed values, may introduce dynamics that are not present in a specific patient. As parameter numbers and model complexity increase, more clinical data is required for validation and the model limitations are harder to quantify. This paper considers the modeling and the parameter identification simultaneously, and creates models that are one to one with the measurements. That is, every input parameter into the model is uniquely optimized to capture the clinical data and no parameters are set at population values. The result is a geometrical characterization of a previously developed six chamber heart model, and a completely patient specific approach to cardiac diagnosis in critical care. In addition, simplified sub-structures of the six chamber model are created to provide very fast and accurate parameter identification from arbitrary starting points and with no prior knowledge on the parameters. Furthermore, by utilizing continuous information from the arterial/pulmonary pressure waveforms and the end-diastolic time, it is shown that only the stroke volumes of the ventricles are required for adequate cardiac diagnosis. This reduced data set is more practical for an intensive care unit as the maximum and minimum volumes are no longer needed, which was a requirement in prior work. The simplified models can also act as a bridge to identifying more sophisticated cardiac models, by providing a generating set of waveforms that the complex models can match to. Most importantly, this approach does not have any predefined assumptions on patient dynamics other than the basic model structure, and is thus suitable for improving cardiovascular management in critical care by optimizing therapy for individual patients. © 2009 IFAC. [less ▲]

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See detailModel-based Cardiovascular Therapeutics: Capturing the patient-specific impact of inotrope therapy
Desaive, Thomas ULg; Starfinger, C; Chase, JG et al

in Proceedings of the 3rd International Meeting of the French Society of Hypertension (2009)

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See detailRobust parameter identification for model-based cardiac diagnosis in critical care
Hann, C. E.; Chase, J. C.; Desaive, Thomas ULg et al

in Proceedings of the 6th IFAC Symposium on Modeling and Control in Biomedical Systems (MCBMS09) (2009)

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See detailPatient specific model of the cardiovascular system during septic shock
Desaive, Thomas ULg; Chase, J. G.; Lambermont, Bernard ULg et al

in Intensive Care Medicine (2009), 35(suppl. 1), 80

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See detailModel-based therapeutics for the cardiovascular system - a clinical focus
Hann, C. E.; Chase, J. G.; Desaive, Thomas ULg et al

in 6th IFAC Symposium on Modeling and Control in Biomedical Systems (MCBMS09) (2009)

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See detailModel-Based Assessment of Dynamic FRC (DFRC)
Desaive, Thomas ULg; Chase, J. G.; Sundaresan, A. et al

in Intensive Care Medicine (2009), 35(suppl. 1), 52

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See detailWhat makes TGC protocols “T” (tight)? An analysis of data from 2 studies
Suhaimi, F.; LeCompte, A. J.; Preiser, Jean-Charles ULg et al

in Proc 9th Annual Diabetes Technology Meeting (DTM2009) (2009)

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See detailEffective arterial elastance as an index of pulmonary vascular load.
Morimont, Philippe ULg; Lambermont, Bernard ULg; Ghuysen, Alexandre ULg et al

in American Journal of Physiology - Heart and Circulatory Physiology (2008), 294(6), 2736-42

The aim of this study was to test whether the simple ratio of right ventricular (RV) end-systolic pressure (Pes) to stroke volume (SV), known as the effective arterial elastance (Ea), provides a valid ... [more ▼]

The aim of this study was to test whether the simple ratio of right ventricular (RV) end-systolic pressure (Pes) to stroke volume (SV), known as the effective arterial elastance (Ea), provides a valid assessment of pulmonary arterial load in case of pulmonary embolism- or endotoxin-induced pulmonary hypertension. Ventricular pressure-volume (PV) data (obtained with conductance catheters) and invasive pulmonary arterial pressure and flow waveforms were simultaneously recorded in two groups of six pure Pietran pigs, submitted either to pulmonary embolism (group A) or endotoxic shock (group B). Measurements were obtained at baseline and each 30 min after injection of autologous blood clots (0.3 g/kg) in the superior vena cava in group A and after endotoxin infusion in group B. Two methods of calculation of pulmonary arterial load were compared. On one hand, Ea provided by using three-element windkessel model (WK) of the pulmonary arterial system [Ea(WK)] was referred to as standard computation. On the other hand, similar to the systemic circulation, Ea was assessed as the ratio of RV Pes to SV [Ea(PV) = Pes/SV]. In both groups, although the correlation between Ea(PV) and Ea(WK) was excellent over a broad range of altered conditions, Ea(PV) systematically overestimated Ea(WK). This offset disappeared when left atrial pressure (Pla) was incorporated into Ea [Ea * (PV) = (Pes - Pla)/SV]. Thus Ea * (PV), defined as the ratio of RV Pes minus Pla to SV, provides a convenient, useful, and simple method to assess the pulmonary arterial load and its impact on the RV function. [less ▲]

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See detailModel-based diagnosis of acute pulmonary embolism - results from a porcine model
Desaive, Thomas ULg; Ghuysen, Alexandre ULg; Kolh, Philippe ULg et al

in Intensive Care Medicine (2008), 34(suppl. 1), 78

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See detailThe impact of model-based therapeutics on glucose control in an intensive care unit
Hann, C. E.; Chase, J. G.; Desaive, Thomas ULg et al

in IFMBE Proceedings (2008), 22

This paper investigates the impact of fast parameter identification methods, which do not require any forward simulations, on model-based glucose control, using retrospective data in the Christchurch ... [more ▼]

This paper investigates the impact of fast parameter identification methods, which do not require any forward simulations, on model-based glucose control, using retrospective data in the Christchurch Hospital Intensive Care Unit. The integral-based identification method has been previously clinically validated and extensively applied in a number of biomedical applications; and is a crucial element in the presented model-based therapeutics approach. Common non-linear regression and gradient descent approaches are too computationally intense and not suitable for the glucose control applications presented. The main focus in this paper is on better characterizing and understanding the importance of the integral in the formulation and the effect it has on model-based drug therapy control. As a comparison, a potentially more natural derivative formulation which has the same computation speed advantages is investigated, and is shown to go unstable with respect to modelling error which is always present clinically. The integral method remains robust. © 2009 Springer Berlin Heidelberg. [less ▲]

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See detailThe impact of model-based therapeutics on glucose control in an intensive care unit
Chase, JG; Hann, CE; Desaive, Thomas ULg et al

in Proceedings of the 4th European Congress for Medical and Biomedical Engineering (eMBEC 2008) (2008)

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See detailModel-based identification and diagnosis of a porcine model of induced endotoxic shock with hemofiltration
Starfinger, C.; Chase, J. G.; Hann, C. E. et al

in Mathematical Biosciences (2008), 216(2), 132-139

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See detailAlteration of Right Ventricular-Pulmonary Vascular Coupling in a Porcine Model of Progressive Pressure Overloading
Ghuysen, Alexandre ULg; Lambermont, Bernard ULg; Kolh, Philippe ULg et al

in Shock (Augusta, Ga.) (2008), 29(2), 197-204

In acute pulmonary embolism, right ventricular (RV) failure may result from exceeding myocardial contractile resources with respect to the state of vascular afterload. We investigated the adaptation of RV ... [more ▼]

In acute pulmonary embolism, right ventricular (RV) failure may result from exceeding myocardial contractile resources with respect to the state of vascular afterload. We investigated the adaptation of RV performance in a porcine model of progressive pulmonary embolism. Twelve anesthetized pigs were randomly divided into two groups: gradual pulmonary arterial pressure increases by three injections of autologous blood clot (n = 6) or sham-operated controls (n = 6). Right ventricular pressure-volume (PV) loops were recorded using a conductance catheter. Right ventricular contractility was estimated by the slope of the end-systolic PV relationship (Ees). Afterload was referred to as pulmonary arterial elastance (Ea) and assessed using a four-element Windkessel model. Right ventricular-arterial coupling (Ees/Ea) and efficiency of energy transfer (from PV area to external mechanical work [stroke work]) were assessed at baseline and every 30 min for 4 h. Eaincreased progressively after embolization, from 0.26 +/- 0.04 to 2.2 +/- 0.7 mmHg mL (P < 0.05). Ees increased from 1.01 +/-0.07 to 2.35 +/- 0.27 mmHg mL (P < 0.05) after the first two injections but failed to increase any further. As a result, Ees/Ea initially decreased to values associated with optimal SW, but the last injection was responsible for Ees/Ea values less than 1, decreased stroke volume, and RV dilation. Stroke work/PV area consistently decreased with each injection from 79% +/- 3% to 39% +/- 11% (P < 0.05). In response to gradual increases in afterload, RV contractility reserve was recruited to a point of optimal coupling but submaximal efficiency. Further afterload increases led to RV-vascular uncoupling and failure. [less ▲]

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See detailDiagnosing Cardiac Dysfunction and Guiding Therapy in Critical Care
Starfinger, C.; Chase, J. G.; Hann, C. et al

in Proceedings of the NZBio 2008 Conference & Exposition, (2008)

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See detailMathematical modelling and parameter identification methods in systems
Hann, C. E.; Chase, J. G.; Shaw, G. M. et al

in Proceedings of the 7th joint Australia-New Zealand Mathematics Convention (ANZMC2008) (2008)

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See detailModel-based detection of pulmonary embolism using an extended physiologically relevant, cardiovascular model
Kok, K.; Starfinger, C.; Hann, C. E. et al

in Proceedings of Engineering & Physical Sciences in Medicine and Australian Biomedical Engineering Conference (EPSM ABEC 2008) (2008)

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