References of "LAMBERMONT, Bernard"
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See detailPulmonary embolism diagnostics from the driver function
Stevenson, DJ; Revie; Chase, JG et al

in Critical Care (2011), 15 (Suppl 1)

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See detailModel-based cardiovascular monitoring of acute pulmonary embolism in porcine trials
Revie, JA; Stevenson, DJ; Chase, JG et al

in Critical Care (2011), 15 (Suppl 1)

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See detailModel-based cardiovascular monitoring of large pore hemofiltration during endotoxic shock in pigs
Revie, JA; Stevenson, DJ; Chase, JG et al

in Critical Care (2011), 15 (Suppl 1)

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See detailPatient specific identification of the cardiac driver function in a cardiovascular system model.
Hann, C. E.; Revie, J.; Stevenson, D. et al

in Computer Methods & Programs in Biomedicine (2011)

The cardiac muscle activation or driver function, is a major determinant of cardiovascular dynamics, and is often approximated by the ratio of the left ventricle pressure to the left ventricle volume. In ... [more ▼]

The cardiac muscle activation or driver function, is a major determinant of cardiovascular dynamics, and is often approximated by the ratio of the left ventricle pressure to the left ventricle volume. In an intensive care unit, the left ventricle pressure is usually never measured, and the left ventricle volume is only measured occasionally by echocardiography, so is not available real-time. This paper develops a method for identifying the driver function based on correlates with geometrical features in the aortic pressure waveform. The method is included in an overall cardiovascular modelling approach, and is clinically validated on a porcine model of pulmonary embolism. For validation a comparison is done between the optimized parameters for a baseline model, which uses the direct measurements of the left ventricle pressure and volume, and the optimized parameters from the approximated driver function. The parameters do not significantly change between the two approaches thus showing that the patient specific approach to identifying the driver function is valid, and has potential clinically. [less ▲]

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See detailPorcine trial validation of model-based cardiovascular monitoring of acute pulmonary embolism
Revie, JA; Stevenson, DJ; Shaw, GM et al

in Proceedings of ANZICS 2011 (2011)

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See detailDiagnosing pulmonary embolism from a model-based cardiac driver function
Stevenson, D; Revie, JA; Chase, JG et al

in Proceedings of ANZICS 2011 (2011)

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See detailProcessing aortic and pulmonary artery waveforms to derive the ventricle time-varying elastance
Stevenson, D; Chase, JG; Hann, CE et al

in Proceedings of the 18th IFAC World Congress, 2011 (2011)

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See detailNeurally Adjusted Ventilatory Assist (NAVA) improves the matching of diaphragmatic electrical activity and tidal volume in comparison to pressure support (PS)
Piquilloud, L; Chiew, YS; Bialais, E et al

in Intensive Care Medicine (2011), 37 (Suppl 1)

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See detailPatient-ventilator synchrony and tidal volume variability using NAVA and pressure support mechanical ventilation modes
Moorhead, K. T.; Piquilloud, L.; LAMBERMONT, Bernard ULg et al

in Proceedings of the 18th IFAC world congress, 2011 (2011)

Neurally Adjusted Ventilatory Assist (NAVA) is a new ventilatory mode in which ventilator settings are adjusted based on the electrical activity detected in the diaphragm (Eadi). This mode offers ... [more ▼]

Neurally Adjusted Ventilatory Assist (NAVA) is a new ventilatory mode in which ventilator settings are adjusted based on the electrical activity detected in the diaphragm (Eadi). This mode offers significant advantages in mechanical ventilation over standard pressure support (PS) modes, since ventilator input is determined directly from patient ventilatory demand. A comparative study of 22 patients undergoing mechanical ventilation in both PS and NAVA modes was conducted, and it was concluded that for a given variability in Eadi, there is greater variability in tidal volume and correlation between the tidal volume and the diaphragmatic electrical activity with NAVA compared to PS. These results are consistent with the improved patient-ventilator synchrony reported in the literature. © 2011 IFAC. [less ▲]

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See detailModel-based diagnosis of acute pulmonary embolism and septic shock in porcine trials
Revie, JA; Stevenson, D; Chase, JG et al

in Proceedings of the Health Research Society of Christchurch Annual Scientific Session 2011 (2011)

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See detailProcessing aortic and pulmonary artery waveforms to derive the ventricle time-varying elastance
Stevenson, D. J.; Hann, C. E.; Chase, G. J. et al

in IFAC Proceedings Volumes (IFAC-PapersOnline) (2011), 18(PART 1), 587-592

Time-varying elastance of the ventricles is an important metric both clinically and as an input for a previously developed cardiovascular model. However, currently time-varying elastance is not normally ... [more ▼]

Time-varying elastance of the ventricles is an important metric both clinically and as an input for a previously developed cardiovascular model. However, currently time-varying elastance is not normally available in an Intensive Care Unit (ICU) setting, as it is an invasive and ethically challenging metric to measure. A previous paper developed a method to map less invasive metrics to the driver function, enabling an estimate to be achieved without invasive measurements. This method requires reliable and accurate processing of the aortic and pulmonary artery pressure waveforms to locate the specific points that are required to estimate the driver function. This paper details the method by which these waveforms are processed, using a data set of five pigs induced with pulmonary embolism, and five pigs induced with septic shock (with haemofiltration), adding up to 88 waveforms (for each of aortic and pulmonary artery pressure), and 616 points in total to locate. 98.2% of all points were located to within 1% of their true value, 0.81% were between 1% and 5%, 0.65% were between 5% and 10%, the remaining 0.32% were below 20%.© 2011 IFAC. [less ▲]

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See detailComparison of the Full Outline of UnResponsiveness and Glasgow Liege Scale/Glasgow Coma Scale in an Intensive Care Unit Population.
Bruno, Marie-Aurélie ULg; LEDOUX, Didier ULg; LAMBERMONT, Bernard ULg et al

in Neurocritical Care (2011), 15(3), 447-53

BACKGROUND: The Full Outline of UnResponsiveness (FOUR) has been proposed as an alternative for the Glasgow Coma Scale (GCS)/Glasgow Liege Scale (GLS) in the evaluation of consciousness in severely brain ... [more ▼]

BACKGROUND: The Full Outline of UnResponsiveness (FOUR) has been proposed as an alternative for the Glasgow Coma Scale (GCS)/Glasgow Liege Scale (GLS) in the evaluation of consciousness in severely brain-damaged patients. We compared the FOUR and GLS/GCS in intensive care unit patients who were admitted in a comatose state. METHODS: FOUR and GLS evaluations were performed in randomized order in 176 acutely (<1 month) brain-damaged patients. GLS scores were transformed in GCS scores by removing the GLS brainstem component. Inter-rater agreement was assessed in 20% of the studied population (N = 35). A logistic regression analysis adjusted for age, and etiology was performed to assess the link between the studied scores and the outcome 3 months after injury (N = 136). RESULTS: GLS/GCS verbal component was scored 1 in 146 patients, among these 131 were intubated. We found that the inter-rater reliability was good for the FOUR score, the GLS/GCS. FOUR, GLS/GCS total scores predicted functional outcome with and without adjustment for age and etiology. 71 patients were considered as being in a vegetative/unresponsive state based on the GLS/GCS. The FOUR score identified 8 of these 71 patients as being minimally conscious given that these patients showed visual pursuit. CONCLUSIONS: The FOUR score is a valid tool with good inter-rater reliability that is comparable to the GLS/GCS in predicting outcome. It offers the advantage to be performable in intubated patients and to identify non-verbal signs of consciousness by assessing visual pursuit, and hence minimal signs of consciousness (11% in this study), not assessed by GLS/GCS scales. [less ▲]

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See detailClinical detection and monitoring of acute pulmonary embolism: proof of concept of a computer-based method.
Revie, James A; Stevenson, David J; Chase, J Geoffrey et al

in Annals of Intensive Care (2011), 1(1), 33

ABSTRACT: BACKGROUND: The diagnostic ability of computer-based methods for cardiovascular system (CVS) monitoring offers significant clinical potential. This research tests the clinical applicability of a ... [more ▼]

ABSTRACT: BACKGROUND: The diagnostic ability of computer-based methods for cardiovascular system (CVS) monitoring offers significant clinical potential. This research tests the clinical applicability of a newly improved computer-based method for the proof of concept case of tracking changes in important hemodynamic indices due to the influence acute pulmonary embolism (APE). METHODS: Hemodynamic measurements from a porcine model of APE were used to validate the method. Of these measurements, only those that are clinically available or inferable were used in to identify pig-specific computer models of the CVS, including the aortic and pulmonary artery pressure, stroke volume, heart rate, global end diastolic volume, and mitral and tricuspid valve closure times. Changes in the computer-derived parameters were analyzed and compared with experimental metrics and clinical indices to assess the clinical applicability of the technique and its ability to track the disease state. RESULTS: The subject-specific computer models accurately captured the increase in pulmonary resistance (Rpul), the main cardiovascular consequence of APE, in all five pigs trials, which related well (R2 = 0.81) with the experimentally derived pulmonary vascular resistance. An increase in right ventricular contractility was identified, as expected, consistent with known reflex responses to APE. Furthermore, the modeled right ventricular expansion index (the ratio of right to left ventricular end diastolic volumes) closely followed the trends seen in the measured data (R2 = 0.92) used for validation, with sharp increases seen in the metric for the two pigs in a near-death state. These results show that the pig-specific models are capable of tracking disease-dependent changes in pulmonary resistance (afterload), right ventricular contractility (inotropy), and ventricular loading (preload) during induced APE. Continuous, accurate estimation of these fundamental metrics of cardiovascular status can help to assist clinicians with diagnosis, monitoring, and therapy-based decisions in an intensive care environment. Furthermore, because the method only uses measurements already available in the ICU, it can be implemented with no added risk to the patient and little extra cost. CONCLUSIONS: This computer-based monitoring method shows potential for real-time, continuous diagnosis and monitoring of acute CVS dysfunction in critically ill patients. [less ▲]

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See detailEnd of life care in the operating room for non-heart-beating donors: organization at the University Hospital of Liege.
JORIS, Jean ULg; KABA, Abdourahmane ULg; LAUWICK, Séverine ULg et al

in Transplantation Proceedings (2011), 43(9), 3441-4

Non-heart-beating (NHB) organ donation has become an alternative source to increase organ supply for transplantation. A NHB donation program was implemented in our institution in 2002. As in many ... [more ▼]

Non-heart-beating (NHB) organ donation has become an alternative source to increase organ supply for transplantation. A NHB donation program was implemented in our institution in 2002. As in many institutions the end of life care of the NHB donor (NHBD) is terminated in the operating room (OR) to reduce warm ischemia time. Herein we have described the organization of end of life care for these patients in our institution, including the problems addressed, the solution proposed, and the remaining issues. Emphasis is given to our protocol elaborated with the different contributors of the chain of the NHB donation program. This protocol specifies the information mandatory in the medical records, the end of life care procedure, the determination of death, and the issue of organ preservation measures before NHBD death. The persisting malaise associated with NHB donation reported by OR nurses is finally documented using an anonymous questionnaire. [less ▲]

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See detailSubject-specific cardiovascular system model-based identification and diagnosis of septic shock with a minimally invasive data set: animal experiments and proof of concept.
Chase, J Geoffrey; Lambermont, Bernard ULg; Starfinger, Christina et al

in Physiological Measurement (2011), 32(1), 65-82

A cardiovascular system (CVS) model and parameter identification method have previously been validated for identifying different cardiac and circulatory dysfunctions in simulation and using porcine models ... [more ▼]

A cardiovascular system (CVS) model and parameter identification method have previously been validated for identifying different cardiac and circulatory dysfunctions in simulation and using porcine models of pulmonary embolism, hypovolemia with PEEP titrations and induced endotoxic shock. However, these studies required both left and right heart catheters to collect the data required for subject-specific monitoring and diagnosis-a maximally invasive data set in a critical care setting although it does occur in practice. Hence, use of this model-based diagnostic would require significant additional invasive sensors for some subjects, which is unacceptable in some, if not all, cases. The main goal of this study is to prove the concept of using only measurements from one side of the heart (right) in a 'minimal' data set to identify an effective patient-specific model that can capture key clinical trends in endotoxic shock. This research extends existing methods to a reduced and minimal data set requiring only a single catheter and reducing the risk of infection and other complications-a very common, typical situation in critical care patients, particularly after cardiac surgery. The extended methods and assumptions that found it are developed and presented in a case study for the patient-specific parameter identification of pig-specific parameters in an animal model of induced endotoxic shock. This case study is used to define the impact of this minimal data set on the quality and accuracy of the model application for monitoring, detecting and diagnosing septic shock. Six anesthetized healthy pigs weighing 20-30 kg received a 0.5 mg kg(-1) endotoxin infusion over a period of 30 min from T0 to T30. For this research, only right heart measurements were obtained. Errors for the identified model are within 8% when the model is identified from data, re-simulated and then compared to the experimentally measured data, including measurements not used in the identification process for validation. Importantly, all identified parameter trends match physiologically and clinically and experimentally expected changes, indicating that no diagnostic power is lost. This work represents a further with human subjects validation for this model-based approach to cardiovascular diagnosis and therapy guidance in monitoring endotoxic disease states. The results and methods obtained can be readily extended from this case study to the other animal model results presented previously. Overall, these results provide further support for prospective, proof of concept clinical testing with humans. [less ▲]

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See detailContribution of donors after cardiac death to the deceased donor pool: 2002 to 2009 university of liege experience.
Ledinh, H.; Meurisse, Nicolas ULg; Delbouille, Michèle ULg et al

in Transplantation Proceedings (2010), 42(10), 4369-72

OBJECTIVE: In this study, we have evaluated the organ procurement and transplantation activity from donors after cardiac death (DCD) at our institution over an 8-year period. Our aim was to determine ... [more ▼]

OBJECTIVE: In this study, we have evaluated the organ procurement and transplantation activity from donors after cardiac death (DCD) at our institution over an 8-year period. Our aim was to determine whether this program influenced transplantation programs, or donation after brain death (DBD) activity. METHODS: We prospectively collected our procurement and transplantation statistics in a database for retrospective review. RESULTS: We observed an increasing trend in potential and actual DCD number. The mean conversion rate turning potential into effective donors was 58.1%. DCD accounted for 16.6% of the deceased donor (DD) pool over 8 years. The mean age for effective DCD donors was 53.9 years (range, 3-79). Among the effective donors, 63.3% (n = 31) came from the transplant center and 36.7% (n = 18) were referred from collaborative hospitals. All donors were Maastricht III category. The number of kidney and liver transplants using DCD sources tended to increase. DCD kidney transplants represented 10.8% of the DD kidney pool and DCD liver transplants made up 13.9% of the DD liver pool over 8 years. The DBD program activity increased in the same time period. In 2009, 17 DCD and 33 DBD procurements were performed in a region with a little >1 million inhabitants. CONCLUSION: The establishment of a DCD program in our institution enlarged the donor pool and did not compromise the development of the DBD program. In our experience, DCD are a valuable source for abdominal organ transplantation. [less ▲]

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See detailminimal cardiovascular system model including physiological mitral valve opening
Paeme, Sabine ULg; Moorhead, Katherine ULg; chase, J. Geoffrey et al

in 9th Belgian National Day on Biomedical Engineering, Bruxelles, 26th november (2010, November 26)

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

A minimal cardiovascular system (CVS) model has been previously validated in silico, and in several animal model studies. It accounts for valve dynamics by means of a Heaviside function to simulate the “open on pressure, close on flow” law. However, this model does not describe the progressive valve opening and therefore, it is not suitable for studying valve dysfunctions. [less ▲]

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See detailMinimal cardiovascular system model including physiological mitral valve opening
Paeme, Sabine ULg; Moorhead, Katherine ULg; Chase, J. Geoffrey et al

Poster (2010, November 26)

This research describes a new closed-loop cardiovascular system (CVS) model including a model of the left atrium and a model describing the progressive aperture of the mitral valve

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See detailMathematical model of the mitral valve and the cardiovascular system, application for studying, monitoring and in the diagnosis of valvular pathologies
Paeme, Sabine ULg; Moorhead, Katherine ULg; Chase, J. Geoffrey et al

in UKACC international Conference on Control 2010 : Coventry, 7-10 september 2010 (2010, September 07)

A cardiovascular and circulatory system (CVS) model has been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiological ... [more ▼]

A cardiovascular and circulatory system (CVS) model has been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiological accurate “open on pressure, close on flow” law. Thus, it does not consider the real time scale of the valve aperture dynamics and thus doesn’t fully capture valve dysfunction particularly where the dysfunction involves partial closure. This research describes a new closed-loop CVS model including a model describing the progressive aperture of the mitral valve and valid over the full cardiac cycle. This new model is solved for a healthy and diseased mitral valve. [less ▲]

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