References of "Desaive, Thomas"
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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 detailStroke Volume Estimation using Aortic Pressure Measurements and Aortic Cross Sectional Area
Kamoi, Shun; Pretty, Christopher G.; Chiew, Yeong Shiong et al

Poster (2015, August)

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of ... [more ▼]

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of measurement devices. Current devices for indirect monitoring of SV are shown to be inaccurate during sudden hemodynamic changes. This paper presents a novel SV estimation using readily available aortic pressure measurements and aortic cross sectional area, using data from a porcine experiment where medical interventions such as fluid replacement, dobutamine infusions, and recruitment maneuvers induced SV changes in a pig with circulatory shock. Measurement of left ventricular volume, proximal aortic pressure, and descending aortic pressure waveforms were made simultaneously during the experiment. From measured data, proximal aortic pressure was separated into reservoir and excess pressures. Beat-to-beat aortic characteristic impedance values were calculated using both aortic pressure measurements and an estimate of the aortic cross sectional area. SV was estimated using the calculated aortic characteristic impedance and excess component of the proximal aorta. The median difference between directly measured SV and estimated SV was -1.4ml with 95% limit of agreement +/- 6.6ml. This method demonstrates that SV can be accurately captured beat-to-beat during sudden changes in hemodynamic state. This novel SV estimation could enable improved cardiac and circulatory treatment in the critical care environment by titrating treatment to the effect on SV. [less ▲]

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See detailModelling of the Nonlinear End-Systolic Pressure-Volume Relation and Volume-at-Zero-Pressure in Porcine Experiments
Davidson, Shaun M.; Kannangara, D. Oliver; Pretty, Christopher G. et al

Poster (2015, August)

The End-Systolic Pressure-Volume Relation (ESPVR) is generally modelled as a linear relationship between P and V as cardiac reflexes, such as the baroreflex, are typically suppressed in experiments ... [more ▼]

The End-Systolic Pressure-Volume Relation (ESPVR) is generally modelled as a linear relationship between P and V as cardiac reflexes, such as the baroreflex, are typically suppressed in experiments. However, ESPVR has been observed to behave in a curvilinear fashion when cardiac reflexes are not supressed, suggesting the curvilinear function may be more clinically appropriate. Data was gathered from 41 vena cava occlusion manoeuvres performed experimentally at a variety of PEEPs across 6 porcine specimens, and ESPVR determined for each pig. An exponential model of ESPVR was found to provide a higher correlation coefficient than a linear model in 6 out of 7 cases, and a lower Akaike Information Criterion (AIC) value in all cases. Further, the exponential ESPVR provided positive V0 values in a physiological range in6 out of 7 cases analysed, while the linear ESPVR produced positive V0 values in only 3 out of 7 cases, suggesting linear extrapolation of ESPVR to determine V0 may be flawed. [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 ▲]

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See detailVeno-venous extracorporeal CO2 removal improves pulmonary hemodynamics in a porcine ARDS model
MORIMONT, Philippe ULg; GUIOT, Julien ULg; Desaive, Thomas ULg et al

in Acta Anaesthesiologica Scandinavica (2015)

BACKGROUND: Protective lung ventilation is recommended in patients with acute respiratory distress syndrome (ARDS) to minimize additional injuries to the lung. However, hypercapnic acidosis resulting from ... [more ▼]

BACKGROUND: Protective lung ventilation is recommended in patients with acute respiratory distress syndrome (ARDS) to minimize additional injuries to the lung. However, hypercapnic acidosis resulting from ventilation at lower tidal volume enhances pulmonary hypertension and might induce right ventricular (RV) failure. We investigated if extracorporeal veno-venous CO2 removal therapy could have beneficial effects on pulmonary circulation and RV function. METHODS: This study was performed on an experimental model of ARDS obtained in eight anaesthetized pigs connected to a volume-cycled ventilator. A micromanometer-tipped catheter was inserted into the main pulmonary artery and an admittance micromanometer-tipped catheter was inserted into the right ventricle. RV-arterial coupling was derived from RV pressure-volume loops. ARDS was obtained by repeated bronchoalveolar lavage. Protective ventilation was then achieved, and the pigs were connected to a pump-driven extracorporeal membrane oxygenator (PALP, Maquet, Germany) in order to achieve CO2 removal. RESULTS: ARDS induced severe hypercapnic acidosis. Systolic pulmonary artery pressure significantly increased from 29.6 ± 1.8 to 43.9 ± 2.0 mmHg (P < 0.001). After the PALP was started, acidosis was corrected and normocarbia was maintained despite protective ventilation. Pulmonary artery pressure significantly decreased to 31.6 ± 3.2 mmHg (P < 0.001) and RV-arterial coupling significantly improved (RV-arterial coupling index = 1.03 ± 0.33 vs. 0.55 ± 0.41, P < 0.05). CONCLUSION: Veno-venous CO2 removal therapy enabled protective ventilation while maintaining normocarbia during ARDS. CO2 removal decreased pulmonary hypertension and improved RV function. This technique may be an effective lung- and RV-protective adjunct to mechanical ventilation. [less ▲]

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See detailContinuous Glucose Monitoring: Using CGM to Guide Insulin Therapy Virtual Trials Results
Mombaerts, L.; Thomas, Felicity Louise ULg; Signal, M.K et al

Poster (2015)

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See detailContinuous glucose monitoring: Using cgm to guide insulin therapy virtual trials results
Mombaerts, L.; Thomas, Felicity Louise ULg; Signal, M. et al

in IFAC Proceedings Volumes (IFAC-PapersOnline) (2015), 48(20), 112-117

Continuous glucose monitoring (CGM) devices can measure blood glucose levels through interstitial measurements almost continuously (1-5min sampling period). However, they are not as accurate as glucose ... [more ▼]

Continuous glucose monitoring (CGM) devices can measure blood glucose levels through interstitial measurements almost continuously (1-5min sampling period). However, they are not as accurate as glucose readings from blood measurements. The relation between tissue and blood glucose is dynamic and the sensor signal can degrade over time. In addition, CGM readings contains high frequency noise and can drift between measurements. However, maintaining continuous glucose monitoring has the potential to improve the level of glycemic control achieved and reduce nurse workload. For this purpose, a simple model was designed and tested to see the effect of inherent CGM error on the insulin therapy protocol, STAR (Stochastic TARgeted). An error model was generated from 9 patients that had one Guardian Real-Time CGM device (Medtronic Minimed, Northridge, CA, USA) inserted into their abdomen as part of an observation trial assesing the accuracy of CGM measurements compared to a blood gas analyser and glucometer readings. A resulting error model was then used to simulate the outcomes if the STAR protocol was guided by CGM values on 183 virtual patients. CGM alarms for hyper- and hypo-glycaemic region were included to improve patient safety acting as 'guardrails'. The STAR CGM protocol gave good performance and reduced workload by ∼50%, reducing the number of measurements per day per patient from 13 to 7. The number of hypoglycaemic events increased compared to the current STAR from 0.03% <2.2mmol/L to 0.32%. However, in comparison to other published protocols it is still a very low level of hypoglycaemia and less than clinically acceptable value of 5% <4.0mmol/L. More importantly this study shows great promise for the future of CGM and their use in clinic. With the a newer generation of sensors, specifically designed for the ICU, promising less noise and drift suggesting that a reduced nurse workload without compromising safety or performance is with in reach.? © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. [less ▲]

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See detailMachine Learning and Insulin Sensitivity in Determining Outcome in Preterm Infants
Uyttendaele, Vincent; Dickson, JL; Lynn, A et al

Poster (2015)

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See detailInsulin Sensitivity Profile as a Marker for Reduced Outcome in the Neonatal Intensive Care Unit
Uyttendaele, Vincent; Dickson, JL; Lynn, A et al

Poster (2015)

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See detailRelation between global end-diastolic volume and left ventricular end-diastolic volume
Pironet, Antoine ULg; MORIMONT, Philippe ULg; Kamoi, S. et al

in Critical Care (2015), 19(Suppl 1), 175

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See detailTime-varying respiratory system elastance: a physiological model for patients who are spontaneously breathing.
Chiew, Yeong Shiong; Pretty, Christopher; Docherty, Paul D. et al

in PloS one (2015), 10(1), 0114847

BACKGROUND: Respiratory mechanics models can aid in optimising patient-specific mechanical ventilation (MV), but the applications are limited to fully sedated MV patients who have little or no ... [more ▼]

BACKGROUND: Respiratory mechanics models can aid in optimising patient-specific mechanical ventilation (MV), but the applications are limited to fully sedated MV patients who have little or no spontaneously breathing efforts. This research presents a time-varying elastance (Edrs) model that can be used in spontaneously breathing patients to determine their respiratory mechanics. METHODS: A time-varying respiratory elastance model is developed with a negative elastic component (Edemand), to describe the driving pressure generated during a patient initiated breathing cycle. Data from 22 patients who are partially mechanically ventilated using Pressure Support (PS) and Neurally Adjusted Ventilatory Assist (NAVA) are used to investigate the physiology relevance of the time-varying elastance model and its clinical potential. Edrs of every breathing cycle for each patient at different ventilation modes are presented for comparison. RESULTS: At the start of every breathing cycle initiated by patient, Edrs is < 0. This negativity is attributed from the Edemand due to a positive lung volume intake at through negative pressure in the lung compartment. The mapping of Edrs trajectories was able to give unique information to patients' breathing variability under different ventilation modes. The area under the curve of Edrs (AUCEdrs) for most patients is > 25 cmH2Os/l and thus can be used as an acute respiratory distress syndrome (ARDS) severity indicator. CONCLUSION: The Edrs model captures unique dynamic respiratory mechanics for spontaneously breathing patients with respiratory failure. The model is fully general and is applicable to both fully controlled and partially assisted MV modes. [less ▲]

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See detailTracking stressed blood volume during vascular filling experiments
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

in 13th Belgian Day on Biomedical Engineering (2014, November 28)

A three-chamber cardiovascular system model is used to compute stressed blood volume from filling experiments. As previously observed, stressed blood volume is a good predictor of the change in cardiac ... [more ▼]

A three-chamber cardiovascular system model is used to compute stressed blood volume from filling experiments. As previously observed, stressed blood volume is a good predictor of the change in cardiac output after fluid infusion. [less ▲]

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See detailTracking stressed blood volume during vascular filling experiments
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

Poster (2014, November 28)

A three-chamber cardiovascular system model is used to compute stressed blood volume from filling experiments. As previously observed, stressed blood volume is a good predictor of the change in cardiac ... [more ▼]

A three-chamber cardiovascular system model is used to compute stressed blood volume from filling experiments. As previously observed, stressed blood volume is a good predictor of the change in cardiac output after fluid infusion. [less ▲]

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See detailEstimating Ventricular Stroke Work from Aortic Pressure Waveform
Kamoi, Shun; Pretty, Christopher; Chiew, Yeong Shiong et al

Poster (2014, November 28)

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See detailModeling of the cardio-pulmonary system assisted by ECMO
Habran, Simon ULg; Dauby, Pierre ULg; Desaive, Thomas ULg et al

in National Day on Biomedical Engineering 2014 (2014, October)

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See detailModel-Based Computation of Total Stressed Blood Volume from a Preload Reduction Experiment
Pironet, Antoine ULg; Desaive, Thomas ULg; Chase, J. Geoffrey et al

Conference (2014, August)

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 resuscitation therapy, which ... [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 resuscitation therapy, which is a treatment for cardiac failure. From an engineering point of view, this parameter dictates the cardiovascular system's dynamic behavior. Current methods to determine this parameter involve repeated phases of circulatory arrests followed by fluid administration. In this work, a method is developed to compute stressed blood volume from preload reduction experiments. 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 most sensitive parameters; and (3) adjust only these sensitive parameters. Stressed blood volume was determined sensitive for all datasets, which emphasizes the importance of this parameter. The model was able to track experimental trends with a maximal mean squared error of 11.77 %. Stressed blood volume has been computed to range between 450 and 963 ml, or 15 to 28 ml/kg, which matches previous independent experiments on pigs, dogs and humans. Consequently, the method proposed in this work provides a simple way to compute total stressed blood volume from usual hemodynamic data. [less ▲]

Detailed reference viewed: 33 (8 ULg)