References of "LAMBERMONT, Bernard"
     in
Bookmark and Share    
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 31 (12 ULg)
Full Text
Peer Reviewed
See detailLe couplage ventriculoartériel : du concept aux applications cliniques
Morimont, Philippe ULg; Lambermont, Bernard ULg; Ghuysen, Alexandre ULg et al

in Réanimation (2009), 18(3), 201-206

L’interaction entre le ventricule et le réseau vasculaire est un déterminant majeur de la performance cardiaque globale, particulièrement en présence d’une insuffisance ventriculaire préalable ... [more ▼]

L’interaction entre le ventricule et le réseau vasculaire est un déterminant majeur de la performance cardiaque globale, particulièrement en présence d’une insuffisance ventriculaire préalable. L’évaluation du couplage ventriculoartériel grâce à la mesure de l’élastance ventriculaire, comme reflet de la contractilité et de l’élastance artérielle, en tant qu’indice de post-charge, permet de quantifier cette interaction. Des travaux récents illustrent l’intérêt clinique de ce concept. Jusqu’à présent, son utilisation restait toutefois marginale en raison de la nécessité de recourir à des mesures invasives et complexes. Le développement des techniques d’imagerie non invasive et de traitement des signaux permet actuellement d’envisager l’utilisation de ce concept en pratique clinique courante. [less ▲]

Detailed reference viewed: 61 (12 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 13 (1 ULg)
Full Text
Peer Reviewed
See detailFunctional connectivity in the default network during resting state is preserved in a vegetative but not in a brain dead patient.
Boly, Mélanie ULg; Tshibanda, Luaba ULg; Vanhaudenhuyse, Audrey ULg et al

in Human Brain Mapping (2009), 30(8), 2393-400

Recent studies on spontaneous fluctuations in the functional MRI blood oxygen level-dependent (BOLD) signal in awake healthy subjects showed the presence of coherent fluctuations among functionally ... [more ▼]

Recent studies on spontaneous fluctuations in the functional MRI blood oxygen level-dependent (BOLD) signal in awake healthy subjects showed the presence of coherent fluctuations among functionally defined neuroanatomical networks. However, the functional significance of these spontaneous BOLD fluctuations remains poorly understood. By means of 3 T functional MRI, we demonstrate absent cortico-thalamic BOLD functional connectivity (i.e. between posterior cingulate/precuneal cortex and medial thalamus), but preserved cortico-cortical connectivity within the default network in a case of vegetative state (VS) studied 2.5 years following cardio-respiratory arrest, as documented by extensive behavioral and paraclinical assessments. In the VS patient, as in age-matched controls, anticorrelations could also be observed between posterior cingulate/precuneus and a previously identified task-positive cortical network. Both correlations and anticorrelations were significantly reduced in VS as compared to controls. A similar approach in a brain dead patient did not show any such long-distance functional connectivity. We conclude that some slow coherent BOLD fluctuations previously identified in healthy awake human brain can be found in alive but unaware patients, and are thus unlikely to be uniquely due to ongoing modifications of conscious thoughts. Future studies are needed to give a full characterization of default network connectivity in the VS patients population. [less ▲]

Detailed reference viewed: 81 (20 ULg)
Full Text
Peer Reviewed
See detailAsthme aigu grave: une affection qui demeure redoutable.
D'Orio, Virginie ULg; Ghuysen, Alexandre ULg; Lambermont, Bernard ULg

in Revue Médicale de Liège (2009), 64(7-8), 377-81

Severe exacerbations of asthma can be life-threatening if not aggressively treated. Despite the publication of therapeutic guidelines developed by experts in this field and people education programs ... [more ▼]

Severe exacerbations of asthma can be life-threatening if not aggressively treated. Despite the publication of therapeutic guidelines developed by experts in this field and people education programs, early recognition and characterization of patients at risk for fatal asthma remain scarce. We report the case of a young lady suffering from acute exacerbation of asthma responsible for intensive care admission with long term mechanical ventilation due to the lack in initial appropriate care. [less ▲]

Detailed reference viewed: 147 (26 ULg)
Peer Reviewed
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)

Detailed reference viewed: 14 (4 ULg)
Peer Reviewed
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

Detailed reference viewed: 55 (12 ULg)
Peer Reviewed
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)

Detailed reference viewed: 13 (4 ULg)
Peer Reviewed
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

Detailed reference viewed: 45 (10 ULg)
Full Text
Peer Reviewed
See detailCotrimoxazole induced mixed type II cryoglobulinemia.
Leclercq, Philippe ULg; Frippiat, Frédéric ULg; Lambermont, Bernard ULg

in European Journal of Internal Medicine (2008), 19(4),

Detailed reference viewed: 34 (8 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 87 (8 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 52 (5 ULg)
Full Text
Peer Reviewed
See detailPerception of pain in the minimally conscious state with PET activation: an observational study.
Boly, Mélanie ULg; Faymonville, Marie-Elisabeth ULg; Schnakers, Caroline et al

in Lancet Neurology (2008), 7(11), 1013-20

BACKGROUND: Patients in a minimally conscious state (MCS) show restricted self or environment awareness but are unable to communicate consistently and reliably. Therefore, better understanding of cerebral ... [more ▼]

BACKGROUND: Patients in a minimally conscious state (MCS) show restricted self or environment awareness but are unable to communicate consistently and reliably. Therefore, better understanding of cerebral noxious processing in these patients is of clinical, therapeutic, and ethical relevance. METHODS: We studied brain activation induced by bilateral electrical stimulation of the median nerve in five patients in MCS (aged 18-74 years) compared with 15 controls (19-64 years) and 15 patients (19-75 years) in a persistent vegetative state (PVS) with (15)O-radiolabelled water PET. By way of psychophysiological interaction analysis, we also investigated the functional connectivity of the primary somatosensory cortex (S1) in patients and controls. Patients in MCS were scanned 57 (SD 33) days after admission, and patients in PVS 36 (9) days after admission. Stimulation intensities were 8.6 (SD 6.7) mA in patients in MCS, 7.4 (5.9) mA in controls, and 14.2 (8.7) mA in patients in PVS. Significant results were thresholded at p values of less than 0.05 and corrected for multiple comparisons. FINDINGS: In patients in MCS and in controls, noxious stimulation activated the thalamus, S1, and the secondary somatosensory or insular, frontoparietal, and anterior cingulate cortices (known as the pain matrix). No area was less activated in the patients in MCS than in the controls. All areas of the cortical pain matrix showed greater activation in patients in MCS than in those in PVS. Finally, in contrast with patients in PVS, those in MCS had preserved functional connectivity between S1 and a widespread cortical network that includes the frontoparietal associative cortices. INTERPRETATION: Cerebral correlates of pain processing are found in a similar network in controls and patients in MCS but are much more widespread than in patients in PVS. These findings might be objective evidence of a potential pain perception capacity in patients in MCS, which supports the idea that these patients need analgesic treatment. [less ▲]

Detailed reference viewed: 286 (20 ULg)
Full Text
Peer Reviewed
See detailLe cas clinique du mois. Un cas rare d'épanchement pleural unilatéral: le syndrome d'hyperstimulation des ovaires.
Barile, D.; Bataille, Yoann ULg; Duysinx, Bernard ULg et al

in Revue Médicale de Liège (2008), 63(7-8), 474-9

Ovarian hyperstimulation syndrome is the most severe iatrogenic complication of fertilization modern methods. This syndrome is characterized by a massive cystic ovarian enlargement associated with an ... [more ▼]

Ovarian hyperstimulation syndrome is the most severe iatrogenic complication of fertilization modern methods. This syndrome is characterized by a massive cystic ovarian enlargement associated with an acute body fluid shift. Ascite is the most frequent manifestation of this syndrome. In some rare cases ovarian hyperstimulation syndrome is complicated by massive unilateral pleural effusion without ascite. We describe the case of a 36 year old woman who developed a massive unilateral pleural effusion without ascite. An ovarian hyperstimulation syndrome was diagnosed. Chest tube drainage improved patient parameters and symptoms. We discuss the diagnostic approach of pleural effusions. [less ▲]

Detailed reference viewed: 104 (5 ULg)
Full Text
Peer Reviewed
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

Detailed reference viewed: 14 (4 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 28 (5 ULg)
Peer Reviewed
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)

Detailed reference viewed: 17 (0 ULg)