References of "LAMBERMONT, Bernard"
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See detailDetection of decreased glomerular filtration rate in intensive care units: serum cystatin C versus serum creatinine
DELANAYE, Pierre ULg; CAVALIER, Etienne ULg; Morel, Jérôme et al

in BMC Nephrology (2014), 15(9), 1471-2369

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See detailDoes comfort therapy during controlled donation after circulatory death shorten the life of potential donors?
LEDOUX, Didier ULg; DELBOUILLE, Marie-Hélène ULg; DE ROOVER, Arnaud ULg et al

in Clinical transplantation (2014), 28(1), 47-51

INTRODUCTION: Controlled donation after circulatory death (DCD) remains ethically controversial. The authors developed a controlled DCD protocol in which comfort therapy is regularly used. The aim of this ... [more ▼]

INTRODUCTION: Controlled donation after circulatory death (DCD) remains ethically controversial. The authors developed a controlled DCD protocol in which comfort therapy is regularly used. The aim of this study was to determine whether this policy shortens the DCD donors' life. METHODS: The authors retrospectively analyzed prospectively collected data on patients proposed for DCD at the University Hospital of Liege, Belgium, over a 56-month period. The survival duration of these patients, defined as duration between the time of proposal for DCD and the time of circulatory arrest, was compared between patients who actually donated organs and those who did not. RESULTS: About 128 patients were considered for controlled DCD and 54 (43%) became donors. Among the 74 non-donor patients, 34 (46%) objected to organ donation, 38 patients (51%) were denied by the transplant team for various medical reasons, and two potential DCD donors did not undergo procurement due to logistical and organizational reasons. The survival durations were similar in the DCD donor and non-donor groups. No non-donor patient survived. CONCLUSIONS: Survival of DCD donors is not shortened when compared with non-donor patients. These data support the ethical and respectful approach to potential DCD donors in the authors' center, including regular comfort therapy. [less ▲]

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See detailVisualisation of time-varying respiratory system elastance in experimental ARDS animal models.
van Drunen, Erwin J.; Chiew, Yeong Shiong; Pretty, Christopher et al

in BMC pulmonary medicine (2014), 14

BACKGROUND: Patients with acute respiratory distress syndrome (ARDS) risk lung collapse, severely altering the breath-to-breath respiratory mechanics. Model-based estimation of respiratory mechanics ... [more ▼]

BACKGROUND: Patients with acute respiratory distress syndrome (ARDS) risk lung collapse, severely altering the breath-to-breath respiratory mechanics. Model-based estimation of respiratory mechanics characterising patient-specific condition and response to treatment may be used to guide mechanical ventilation (MV). This study presents a model-based approach to monitor time-varying patient-ventilator interaction to guide positive end expiratory pressure (PEEP) selection. METHODS: The single compartment lung model was extended to monitor dynamic time-varying respiratory system elastance, Edrs, within each breathing cycle. Two separate animal models were considered, each consisting of three fully sedated pure pietrain piglets (oleic acid ARDS and lavage ARDS). A staircase recruitment manoeuvre was performed on all six subjects after ARDS was induced. The Edrs was mapped across each breathing cycle for each subject. RESULTS: Six time-varying, breath-specific Edrs maps were generated, one for each subject. Each Edrs map shows the subject-specific response to mechanical ventilation (MV), indicating the need for a model-based approach to guide MV. This method of visualisation provides high resolution insight into the time-varying respiratory mechanics to aid clinical decision making. Using the Edrs maps, minimal time-varying elastance was identified, which can be used to select optimal PEEP. CONCLUSIONS: Real-time continuous monitoring of in-breath mechanics provides further insight into lung physiology. Therefore, there is potential for this new monitoring method to aid clinicians in guiding MV treatment. These are the first such maps generated and they thus show unique results in high resolution. The model is limited to a constant respiratory resistance throughout inspiration which may not be valid in some cases. However, trends match clinical expectation and the results highlight both the subject-specificity of the model, as well as significant inter-subject variability. [less ▲]

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See detailEarly detection of abnormal left ventricular relaxation in acute myocardial ischemia with a quadratic model.
MORIMONT, Philippe ULg; Pironet, Antoine ULg; Desaive, Thomas ULg et al

in Medical engineering & physics (2014)

AIMS: The time constant of left ventricular (LV) relaxation derived from a monoexponential model is widely used as an index of LV relaxation rate, although this model does not reflect the non-uniformity ... [more ▼]

AIMS: The time constant of left ventricular (LV) relaxation derived from a monoexponential model is widely used as an index of LV relaxation rate, although this model does not reflect the non-uniformity of ventricular relaxation. This study investigates whether the relaxation curve can be better fitted with a "quadratic" model than with the "conventional" monoexponential model and if changes in the LV relaxation waveform due to acute myocardial ischemia could be better detected with the quadratic model. METHODS AND RESULTS: Isovolumic relaxation was assessed with quadratic and conventional models during acute myocardial ischemia performed in 6 anesthetized pigs. Mathematical development indicates that one parameter (Tq) of the quadratic model reflects the rate of LV relaxation, while the second parameter (K) modifies the shape of the relaxation curve. Analysis of experimental data obtained in anesthetized pigs showed that the shape of LV relaxation consistently deviates from the conventional monoexponential decay. During the early phase of acute myocardial ischemia, the rate and non-uniformity of LV relaxation, assessed with the quadratic function, were significantly enhanced. Tq increased by 16% (p<0.001) and K increased by 12% (p<0.001) within 30 and 60min, respectively, after left anterior descending (LAD) coronary artery occlusion. However, no significant changes were observed with the conventional monoexponential decay within 60min of ischemia. CONCLUSIONS: The quadratic model better fits LV isovolumic relaxation than the monoexponential model and can detect early changes in relaxation due to acute myocardial ischemia that are not detectable with conventional methods. [less ▲]

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See detailEffects of Neurally Adjusted Ventilatory Assist (NAVA) levels in non-invasive ventilated patients: titrating NAVA levels with electric diaphragmatic activity and tidal volume matching
Chiew, YS; Chase, JG; LAMBERMONT, Bernard ULg et al

in BioMedical Engineering OnLine (2013)

BACKGROUND: Neurally adjusted ventilatory assist (NAVA) delivers pressure in proportion to diaphragm electrical activity (Eadi). However, each patient responds differently to NAVA levels. This study aims ... [more ▼]

BACKGROUND: Neurally adjusted ventilatory assist (NAVA) delivers pressure in proportion to diaphragm electrical activity (Eadi). However, each patient responds differently to NAVA levels. This study aims to examine the matching between tidal volume (Vt) and patients' inspiratory demand (Eadi), and to investigate patient-specific response to various NAVA levels in non-invasively ventilated patients. METHODS: 12 patients were ventilated non-invasively with NAVA using three different NAVA levels. NAVA100 was set according to the manufacturer's recommendation to have similar peak airway pressure as during pressure support. NAVA level was then adjusted ±50% (NAVA50, NAVA150). Airway pressure, flow and Eadi were recorded for 15 minutes at each NAVA level. The matching of Vt and integral of Eadi (ʃEadi) were assessed at the different NAVA levels. A metric, Range90, was defined as the 5-95% range of Vt/ʃEadi ratio to assess matching for each NAVA level. Smaller Range90 values indicated better matching of supply to demand. RESULTS: Patients ventilated at NAVA50 had the lowest Range90 with median 25.6 uVs/ml [Interquartile range (IQR): 15.4-70.4], suggesting that, globally, NAVA50 provided better matching between ʃEadi and Vt than NAVA100 and NAVA150. However, on a per-patient basis, 4 patients had the lowest Range90 values in NAVA100, 1 patient at NAVA150 and 7 patients at NAVA50. Robust coefficient of variation for ʃEadi and Vt were not different between NAVA levels. CONCLUSIONS: The patient-specific matching between ʃEadi and Vt was variable, indicating that to obtain the best possible matching, NAVA level setting should be patient specific. The Range90 concept presented to evaluate Vt/ʃEadi is a physiologic metric that could help in individual titration of NAVA level. [less ▲]

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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 detailEvaluation of a Model-Based Hemodynamic Monitoring Method in a Porcine Study of Septic Shock
Revie, James; Stevenson, David; Chase, J. Geoffrey et al

in Computational and Mathematical Methods in Medicine (2013)

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See detailNAVA enhances tidal volume and diaphragmatic electro-myographic activity matching: a Range90 analysis of supply and demand
Moorhead, K. T.; Piquilloud, L.; LAMBERMONT, Bernard ULg et al

in Journal of Clinical Monitoring and Computing (2013), 27(1)

Neurally adjusted ventilatory assist (NAVA) is a ventilation assist mode that delivers pressure in proportionality to electrical activity of the diaphragm (Eadi). Compared to pressure support ventilation ... [more ▼]

Neurally adjusted ventilatory assist (NAVA) is a ventilation assist mode that delivers pressure in proportionality to electrical activity of the diaphragm (Eadi). Compared to pressure support ventilation (PS), it improves patient-ventilator synchrony and should allow a better expression of patient's intrinsic respiratory variability. We hypothesize that NAVA provides better matching in ventilator tidal volume (Vt) to patients inspiratory demand. 22 patients with acute respiratory failure, ventilated with PS were included in the study. A comparative study was carried out between PS and NAVA, with NAVA gain ensuring the same peak airway pressure as PS. Robust coefficients of variation (CVR) for Eadi and Vt were compared for each mode. The integral of Eadi (sh{phonetic}Eadi) was used to represent patient's inspiratory demand. To evaluate tidal volume and patient's demand matching, Range90 = 5-95 % range of the Vt/sh{phonetic}Eadi ratio was calculated, to normalize and compare differences in demand within and between patients and modes. In this study, peak Eadi and sh{phonetic}Eadi are correlated with median correlation of coefficients, R > 0.95. Median sh{phonetic}Eadi, Vt, neural inspiratory time (Ti_ <br /> Neural), inspiratory time (Ti) and peak inspiratory pressure (PIP) were similar in PS and NAVA. However, it was found that individual patients have higher or smaller sh{phonetic}Eadi, Vt, Ti_ <br /> Neural, Ti and PIP. CVR analysis showed greater Vt variability for NAVA (p < 0.005). Range90 was lower for NAVA than PS for 21 of 22 patients. NAVA provided better matching of Vt to sh{phonetic}Eadi for 21 of 22 patients, and provided greater variability Vt. These results were achieved regardless of differences in ventilatory demand (Eadi) between patients and modes. © 2012 Springer Science+Business Media New York. [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 detailValidation of subject-specific cardiovascular system models from porcine measurements.
Revie, J. A.; Stevenson, D. J.; Chase, J. G. et al

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

A previously validated mathematical model of the cardiovascular system (CVS) is made subject-specific using an iterative, proportional gain-based identification method. Prior works utilised a complete set ... [more ▼]

A previously validated mathematical model of the cardiovascular system (CVS) is made subject-specific using an iterative, proportional gain-based identification method. Prior works utilised a complete set of experimentally measured data that is not clinically typical or applicable. In this paper, parameters are identified using proportional gain-based control and a minimal, clinically available set of measurements. The new method makes use of several intermediary steps through identification of smaller compartmental models of CVS to reduce the number of parameters identified simultaneously and increase the convergence stability of the method. This new, clinically relevant, minimal measurement approach is validated using a porcine model of acute pulmonary embolism (APE). Trials were performed on five pigs, each inserted with three autologous blood clots of decreasing size over a period of four to five hours. All experiments were reviewed and approved by the Ethics Committee of the Medical Faculty at the University of Liege, Belgium. Continuous aortic and pulmonary artery pressures (P(ao), P(pa)) were measured along with left and right ventricle pressure and volume waveforms. Subject-specific CVS models were identified from global end diastolic volume (GEDV), stroke volume (SV), P(ao), and P(pa) measurements, with the mean volumes and maximum pressures of the left and right ventricles used to verify the accuracy of the fitted models. The inputs (GEDV, SV, P(ao), P(pa)) used in the identification process were matched by the CVS model to errors <0.5%. Prediction of the mean ventricular volumes and maximum ventricular pressures not used to fit the model compared experimental measurements to median absolute errors of 4.3% and 4.4%, which are equivalent to the measurement errors of currently used monitoring devices in the ICU ( approximately 5-10%). These results validate the potential for implementing this approach in the intensive care unit. [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 detailIs extended or continuous infusion of Carbapenems the obvious solution to improve clinical outcomes and reduce mortality?
FRIPPIAT, Frédéric ULg; VERCHEVAL, Christelle ULg; LAMBERMONT, Bernard ULg et al

in Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America (2013), 57(2), 324-325

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See detailReduction in VAP incidence by subglottic secretion drainage and antibiotic consumption in ICU patients
VAN CAUWENBERGE, Isabelle ULg; ANCION, Arnaud ULg; LAMBERMONT, Bernard ULg et al

in Intensive Care Medicine (2013), 39(Suppl 2), 465-4660898

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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 detailNeurally adjusted ventilatory assist (NAVA) improves patient-ventilator interaction during non-invasive ventilation delivered by face mask
Piquilloud, L; Tassaux, D; Bialais, E et al

in Intensive Care Medicine (2012)

PURPOSE: To determine if, compared to pressure support (PS), neurally adjusted ventilatory assist (NAVA) reduces patient-ventilator asynchrony in intensive care patients undergoing noninvasive ventilation ... [more ▼]

PURPOSE: To determine if, compared to pressure support (PS), neurally adjusted ventilatory assist (NAVA) reduces patient-ventilator asynchrony in intensive care patients undergoing noninvasive ventilation with an oronasal face mask. METHODS: In this prospective interventional study we compared patient-ventilator synchrony between PS (with ventilator settings determined by the clinician) and NAVA (with the level set so as to obtain the same maximal airway pressure as in PS). Two 20-min recordings of airway pressure, flow and electrical activity of the diaphragm during PS and NAVA were acquired in a randomized order. Trigger delay (T(d)), the patient's neural inspiratory time (T(in)), ventilator pressurization duration (T(iv)), inspiratory time in excess (T(iex)), number of asynchrony events per minute and asynchrony index (AI) were determined. RESULTS: The study included 13 patients, six with COPD, and two with mixed pulmonary disease. T(d) was reduced with NAVA: median 35 ms (IQR 31-53 ms) versus 181 ms (122-208 ms); p = 0.0002. NAVA reduced both premature and delayed cyclings in the majority of patients, but not the median T(iex) value. The total number of asynchrony events tended to be reduced with NAVA: 1.0 events/min (0.5-3.1 events/min) versus 4.4 events/min (0.9-12.1 events/min); p = 0.08. AI was lower with NAVA: 4.9 % (2.5-10.5 %) versus 15.8 % (5.5-49.6 %); p = 0.03. During NAVA, there were no ineffective efforts, or late or premature cyclings. PaO(2) and PaCO(2) were not different between ventilatory modes. CONCLUSION: Compared to PS, NAVA improved patient ventilator synchrony during noninvasive ventilation by reducing T(d) and AI. Moreover, with NAVA, ineffective efforts, and late and premature cyclings were absent. [less ▲]

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