References of "JANSSEN, Nathalie"
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See detailExpiratory model-based method to monitor ARDS disease state
Van Drunen, EJ; Chiew, YS; Chase, JG et al

in BioMedical Engineering OnLine (2013)

INTRODUCTION: Model-based methods can be used to characterise patient-specific condition and response to mechanical ventilation (MV) during treatment for acute respiratory distress syndrome (ARDS ... [more ▼]

INTRODUCTION: Model-based methods can be used to characterise patient-specific condition and response to mechanical ventilation (MV) during treatment for acute respiratory distress syndrome (ARDS). Conventional metrics of respiratory mechanics are based on inspiration only, neglecting data from the expiration cycle. However, it is hypothesised that expiratory data can be used to determine an alternative metric, offering another means to track patient condition and guide positive end expiratory pressure (PEEP) selection. METHODS: Three fully sedated, oleic acid induced ARDS piglets underwent three experimental phases. Phase 1 was a healthy state recruitment manoeuvre. Phase 2 was a progression from a healthy state to an oleic acid induced ARDS state. Phase 3 was an ARDS state recruitment manoeuvre. The expiratory time-constant model parameter was determined for every breathing cycle for each subject. Trends were compared to estimates of lung elastance determined by means of an end-inspiratory pause method and an integral-based method. All experimental procedures, protocols and the use of data in this study were reviewed and approved by the Ethics Committee of the University of Liege Medical Faculty. RESULTS: The overall median absolute percentage fitting error for the expiratory time-constant model across all three phases was less than 10 %; for each subject, indicating the capability of the model to capture the mechanics of breathing during expiration. Provided the respiratory resistance was constant, the model was able to adequately identify trends and fundamental changes in respiratory mechanics. CONCLUSION: Overall, this is a proof of concept study that shows the potential of continuous monitoring of respiratory mechanics in clinical practice. Respiratory system mechanics vary with disease state development and in response to MV settings. Therefore, titrating PEEP to minimal elastance theoretically results in optimal PEEP selection. Trends matched clinical expectation demonstrating robustness and potential for guiding MV therapy. However, further research is required to confirm the use of such real-time methods in actual ARDS patients, both sedated and spontaneously breathing. [less ▲]

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See detailAssessment of ventricular contractility and ventricular-arterial coupling with a model-based sensor.
Desaive, Thomas ULg; LAMBERMONT, Bernard ULg; JANSSEN, Nathalie ULg et al

in Computer Methods & Programs in Biomedicine (2013), 109(2),

Estimation of ventricular contractility and ventricular arterial coupling is clinically important in diagnosing and treating cardiac dysfunction in the critically ill. However, experimental assessment of ... [more ▼]

Estimation of ventricular contractility and ventricular arterial coupling is clinically important in diagnosing and treating cardiac dysfunction in the critically ill. However, experimental assessment of indexes of ventricular contractility, such as the end-systolic pressure-volume relationship, requires a highly invasive maneuver and measurements that are not typical in an intensive care unit (ICU). This research describes the use of a previously validated cardiovascular system model and parameter identification process to evaluate the right ventricular arterial coupling in septic shock. Model-based ventricular arterial coupling is defined by the ratio of the end systolic right ventricular elastance (E(esrvf)) over the pulmonary artery elastance (E(pa)) or the mean pulmonary inflow resistance (R(pulin)). Results are compared to the clinical gold-standard assessment (conductance catheter method). Six anesthetized healthy pigs weighing 20-30kg received a 0.5mgkg(-1) endotoxin infusion over a period of 30min from T0 to T30, to induce septic shock and veno-venous hemofiltration was used from T60 onward. The results show good agreement with the gold-standard experimental assessment. In particular, the model-based right ventricular elastance (E(esrvf)) correlates well with the clinical gold standard (R(2)=0.69) and the model-based non-invasive coupling (E(esrvf)/R(pulin)) follow the same trends and dynamics (R(2)=0.37). The overall results show the potential to develop a model-based sensor to monitor ventricular-arterial coupling in clinical real-time. [less ▲]

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See detailVisualisation of Time-Variant Respiratory System Elastance in ARDS Models.
Van Drunen, E. J.; Chiew, Y. S.; Zhao, Z. et al

in Biomedizinische Technik. Biomedical engineering (2013), 58(suppl 1)

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See detailEffects of Large-Pore Hemofiltration in a Swine Model of Fulminant Hepatic Failure.
DETRY, Olivier ULg; JANSSEN, Nathalie ULg; CHERAMY-BIEN, Jean-Paul ULg et al

in Artificial Organs (2012), 36(11), 981-987

Among the different potential mechanisms that could lead to brain edema and intracranial hypertension in fulminant hepatic failure (FHF), the inflammatory hypothesis implies that systemic inflammation ... [more ▼]

Among the different potential mechanisms that could lead to brain edema and intracranial hypertension in fulminant hepatic failure (FHF), the inflammatory hypothesis implies that systemic inflammation might be in part responsible for an increase in cerebral blood flow (CBF) and brain water content. In this study, the authors used a validated ischemic FHF swine model to evaluate the effects of 80 kDa large-pore membrane hemofiltration (LPHF) on intracranial pressure (ICP) and CBF, in relation with the clearance of proinflammatory cytokines and blood liver tests, as primary end points. Fifteen pigs were randomized into one of three groups: SHAM, FHF, and FHF + LPHF. All experiments lasted 6 h. In the FHF groups, liver failure was induced by liver ischemia. After 2 h, the FHF + LPHF group underwent 4 h of a zero-balance continuous veno-venous hemofiltration using a 0.7-m(2) , large-pore (78 A) membrane with a cutoff of 80 kDa. ICP, CBF, mean arterial pressure, central venous pressure, and heart rate were continuously monitored and recorded. Arterial aspartate aminotransferase, total bilirubin, creatinine, international normalized ratio, glucose, lactate and serum cytokines interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha were measured at T0, T120, and T360. Over the 6 h following liver ischemia, the FHF group developed a significant increase in ICP. This ICP rise was not observed in the SHAM group and was attenuated in the FHF + LDHF group. However, the ICP levels were not different at T360 in the FHF + LDHF group compared to the FHF group. No significant effect of LPHF on liver tests or levels of proinflammatory cytokines could be demonstrated. In this model, 80 kDa LPHF was not efficient to control FHF intracranial hypertension and to decrease serum cytokine levels. [less ▲]

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See detailArterial dP/dtmax accurately reflects left ventricular contractility during shock when adequate vascular filling is achieved
MORIMONT, Philippe ULg; LAMBERMONT, Bernard ULg; Desaive, Thomas ULg et al

in BMC Cardiovascular Disorders (2012), 12:13

Background: Peak first derivative of femoral artery pressure (arterial dP/dt max) derived from fluid-filled catheter remains questionable to assess left ventricular (LV) contractility during shock. The ... [more ▼]

Background: Peak first derivative of femoral artery pressure (arterial dP/dt max) derived from fluid-filled catheter remains questionable to assess left ventricular (LV) contractility during shock. The aim of this study was to test if arterial dP/dt maxis reliable for assessing LV contractility during various hemodynamic conditions such as endotoxin-induced shock and catecholamine infusion.Methods: Ventricular pressure-volume data obtained with a conductance catheter and invasive arterial pressure obtained with a fluid-filled catheter were continuously recorded in 6 anaesthetized and mechanically ventilated pigs. After a stabilization period, endotoxin was infused to induce shock. Catecholamines were transiently administrated during shock. Arterial dP/dt maxwas compared to end-systolic elastance (Ees), the gold standard method for assessing LV contractility.Results: Endotoxin-induced shock and catecholamine infusion lead to significant variations in LV contractility. Overall, significant correlation (r = 0.51; p < 0.001) but low agreement between the two methods were observed. However, a far better correlation with a good agreement were observed when positive-pressure ventilation induced an arterial pulse pressure variation (PPV) ≤ 11% (r = 0.77; p < 0.001).Conclusion: While arterial dP/dt maxand Ees were significantly correlated during various hemodynamic conditions, arterial dP/dt maxwas more accurate for assessing LV contractility when adequate vascular filling, defined as PPV ≤ 11%, was achieved. © 2012 Morimont et al; licensee BioMed Central Ltd. [less ▲]

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See detailPhysiological relevance and performance of a minimal lung model -- an experimental study in healthy and acute respiratory distress syndrome model piglets
Chiew, Y. S.; Chase, J. G.; LAMBERMONT, Bernard ULg et al

in BMC Pulmonary Medicine (2012), 12:59

Background: Mechanical ventilation (MV) is the primary form of support for acute respiratory distress syndrome (ARDS) patients. However, intra- and inter- patient-variability reduce the efficacy of ... [more ▼]

Background: Mechanical ventilation (MV) is the primary form of support for acute respiratory distress syndrome (ARDS) patients. However, intra- and inter- patient-variability reduce the efficacy of general protocols. Model-based approaches to guide MV can be patient-specific. A physiological relevant minimal model and its patient-specific performance are tested to see if it meets this objective above. Methods: Healthy anesthetized piglets weighing 24.0 kg [IQR: 21.0-29.6] underwent a step-wise PEEP increase manoeuvre from 5cmH2O to 20cmH2O. They were ventilated under volume control using Engstrom Care Station (Datex, General Electric, Finland), with pressure, flow and volume profiles recorded. ARDS was then induced using oleic acid. The data were analyzed with a Minimal Model that identifies patient-specific mean threshold opening and closing pressure (TOP and TCP), and standard deviation (SD) of these TOP and TCP distributions. The trial and use of data were approved by the Ethics Committee of the Medical Faculty of the University of Liege, Belgium.Results and discussions3 of the 9 healthy piglets developed ARDS, and these data sets were included in this study. Model fitting error during inflation and deflation, in healthy or ARDS state is less than 5.0% across all subjects, indicating that the model captures the fundamental lung mechanics during PEEP increase. Mean TOP was 42.4cmH2O [IQR: 38.2-44.6] at PEEP = 5cmH2O and decreased with PEEP to 25.0cmH2O [IQR: 21.5-27.1] at PEEP = 20cmH2O. In contrast, TCP sees a reverse trend, increasing from 10.2cmH2O [IQR: 9.0-10.4] to 19.5cmH2O [IQR: 19.0-19.7]. Mean TOP increased from average 21.2-37.4cmH2O to 30.4-55.2cmH2O between healthy and ARDS subjects, reflecting the higher pressure required to recruit collapsed alveoli. Mean TCP was effectively unchanged. Conclusion: The minimal model is capable of capturing physiologically relevant TOP, TCP and SD of both healthy and ARDS lungs. The model is able to track disease progression and the response to treatment. [less ▲]

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See detailPhysiological Relevance of a Minimal Model in Healthy Pigs Lungs
Chiew, YS; Desaive, Thomas ULg; LAMBERMONT, Bernard ULg et al

in Proceedings of BMS 2012 (2012)

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See detailPerformance of lung recruitment model in healthy anesthetised pigs
Chiew, YS; LAMBERMONT, Bernard ULg; JANSSEN, Nathalie ULg et al

in Proceedings of the World Congress on Medical Physics and Biomedical Engineering 2012 (2012)

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See detailEFFECTS OF LARGE PORE HEMOFILTRATION IN A SWINE MODEL OF FULMINANT HEPATIC FAILURE
DETRY, Olivier ULg; JANSSEN, Nathalie ULg; CHERAMY-BIEN, Jean-Paul ULg et al

in Transplant International (2011, February), 24(1), 10-10

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See detailEffects of large pore hemofiltration in a swine model of fulminant hepatic failure
Detry, Olivier ULg; Janssen, Nathalie ULg; Cheramy-Bien, Jean-Paul ULg et al

in Acta Chirurgica Belgica (2010, April), 110

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See detailEffects of large pore hemofiltration in a swine model of fulminant hepatic failure
Detry, Olivier ULg; Janssen, Nathalie ULg; Cavalier, Etienne ULg et al

in Acta Gastro-Enterologica Belgica (2010), 73(1), 35

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See detailComparison of functional residual capacity and static compliance of the respiratory system during a positive end-expiratory pressure (PEEP) ramp procedure in an experimental model of acute respiratory distress syndrome.
Lambermont, Bernard ULg; Ghuysen, Alexandre ULg; Janssen, Nathalie ULg et al

in Critical Care (2008), 12(4), 91

INTRODUCTION: Functional residual capacity (FRC) measurement is now available on new ventilators as an automated procedure. We compared FRC, static thoracopulmonary compliance (Crs) and PaO2 evolution in ... [more ▼]

INTRODUCTION: Functional residual capacity (FRC) measurement is now available on new ventilators as an automated procedure. We compared FRC, static thoracopulmonary compliance (Crs) and PaO2 evolution in an experimental model of acute respiratory distress syndrome (ARDS) during a reversed, sequential ramp procedure of positive end-expiratory pressure (PEEP) changes to investigate the potential interest of combined FRC and Crs measurement in such a pathologic state. METHODS: ARDS was induced by oleic acid injection in six anesthetised pigs. FRC and Crs were measured, and arterial blood samples were taken after induction of ARDS during a sequential ramp change of PEEP from 20 cm H2O to 0 cm H2O by steps of 5 cm H2O. RESULTS: ARDS was responsible for significant decreases in FRC, Crs and PaO2 values. During ARDS, 20 cm H2O of PEEP was associated with FRC values that increased from 6.2 +/- 1.3 to 19.7 +/- 2.9 ml/kg and a significant improvement in PaO2. The maximal value of Crs was reached at a PEEP of 15 cm H2O, and the maximal value of FRC at a PEEP of 20 cm H2O. From a PEEP value of 15 to 0 cm H2O, FRC and Crs decreased progressively. CONCLUSION: Our results indicate that combined FRC and Crs measurements may help to identify the optimal level of PEEP. Indeed, by taking into account the value of both parameters during a sequential ramp change of PEEP from 20 cm H2O to 0 cm H2O by steps of 5 cm H2O, the end of overdistension may be identified by an increase in Crs and the start of derecruitment by an abrupt decrease in FRC. [less ▲]

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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 detailConfirmation of high cytokine clearance by hemofiltration with a cellulose triacetate membrane with large pores: an in vivo study
Delanaye, Pierre ULg; Lambermont, Bernard ULg; Dogné, Jean-Michel ULg et al

in International Journal of Artificial Organs (2006), 29(10), 944-948

Objective: To confirm in vivo the hypothesis that hemofiltration with a large pore membrane can achieve significant cytokine clearance. Method: We used a well-known animal model of endotoxinic shock (0.5 ... [more ▼]

Objective: To confirm in vivo the hypothesis that hemofiltration with a large pore membrane can achieve significant cytokine clearance. Method: We used a well-known animal model of endotoxinic shock (0.5 mg/kg of lipopolysaccharide from Escherichia Coli over a period of 30 mins). Six pigs were hemofiltrated for 3 hours with a large pore membrane (78 angstrom pore, 80 kDa cut off) (Sureflux FH 70, Nipro, Osaka, Japan). The ultrafiltration rate was 45 ml/kg/min. Samples were taken from arterial, venous line and in the ultrafiltrate at T120 and T240. We measured concentrations of interleukin 6, interleukin 10 and albumin. Results: At T120 and T240, the IL-6 clearances were 22 +/- 7 and 15 +/- 3 ml/min, respectively. The IL-6 sieving coefficients were 0.97 and 0.7 at T120 and T240, respectively. At T120 and T240, the IL-10 clearances were 14 +/- 4 and 10 +/- 7 ml/min, respectively. The sieving coefficients were 0.63 and 0.45 at T120 and T240, respectively. The concentrations of IL-6 and IL-10 were the same at T0 and T240. At T60 and T240, the plasmatic albumin concentrations were 24 +/- 4 g/L and 23 +/- 4 g/L, respectively ( p = 0.13). Conclusions: In this animal model of endotoxinic shock, we confirm the high cytokine clearance observed when hemofiltration is applied to a large pore membrane. The loss of albumin seems negligible. The impact of such clearances on hemodynamic stability and survival remains to be proved. [less ▲]

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See detailDissection coronaire et traumatisme thoracique ferme
Brasseur, Edmond ULg; Ghuysen, Alexandre ULg; Mommens, Véronique et al

in Annales de Cardiologie et d'Angeiologie (2006), 55(4), 233-9

The occurrence of an acute myocardial infarction after non-penetrating chest trauma is an extremely rare complication. We report a case of dissection of the left anterior descending artery in a 43 year ... [more ▼]

The occurrence of an acute myocardial infarction after non-penetrating chest trauma is an extremely rare complication. We report a case of dissection of the left anterior descending artery in a 43 year old man after being punched in the chest. Using data from a literature search relish revealed 76 cases; we review the characteristics of the pathology and its incidence. We also characterize its etiology, anatomy and path physiology. We then consider the diagnostic and therapeutic implications. [less ▲]

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See detailLarge-pore membrane hemofiltration increases cytokine clearance and improves right ventricular-vascular coupling during endotoxic shock in pigs
Lambermont, Bernard ULg; Delanaye, Pierre ULg; Dogné, Jean-Michel ULg et al

in Artificial Organs (2006), 30(7), 560-564

Hemodynamic improvement in patients suffering from both septic shock and renal failure who received hemofiltration suggested that an extrarenal epuration technique could be of interest in patients with ... [more ▼]

Hemodynamic improvement in patients suffering from both septic shock and renal failure who received hemofiltration suggested that an extrarenal epuration technique could be of interest in patients with septic shock alone. However, most of the studies using continuous venovenous hemofiltration (CVVH) in this setting evidenced neither cytokine clearance nor significant reduction in their plasma level. Lack of significant clearance was explained in part by the small size of the membrane pores. Therefore, we investigated the effects of large-pore membrane hemofiltration (LPHF) during endotoxic shock in pigs on interleukin 6 (IL-6) and interleukin 10 (IL-10) clearances, and on right ventricular (RV)-vascular coupling. Thirteen anesthetized healthy pigs weighing 20-30 kg were divided into two groups. In the Endo group (n = 6), the pigs received a 0.5-mg/kg endotoxin infusion over a period of 30 mins from T0 to T30. In the EndoHF group (n = 7), LPHF (cutoff = 80 kDa) and an ultrafiltration rate of 45 mL/kg/h were started 30 mins after the end of the endotoxin infusion, from T60 to T240. In this model of porcine endotoxic shock, LPHF was responsible for a significant clearance of IL-6 (20 mL/min) and Il-10 (14 mL/min), and for an improvement in RV-vascular coupling. [less ▲]

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See detailDynamics of spontaneous ventricular fibrillation in acutely ischemic pigs
Desaive, Thomas ULg; Janssen, Nathalie ULg; Péters, F. et al

in Europace : European Pacing, Arrhythmias, and Cardiac Electrophysiology : Journal of the Working Groups on Cardiac Pacing, Arrhythmias, and Cardiac Cellular Electrophysiology of the European Society of Cardiology (2006), 8 (supplement 1)

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