Conception et réalisation d'un système électronique ambulatoire pour l'évaluation de la microcirculation cutanée

La microcirculation est constituée d un réseau vasculaire qui comprend les artérioles, les veinules et les capillaires. La microcirculation cutanée est un paramètre physiologique important pour les applications cliniques avancées comme le syndrome de Raynaud ou la prévention des escarres. De nombreuses méthodes non ambulatoires ont été développées afin de mesurer la microcirculation sanguine. La tendance actuelle dans le domaine des technologies pour la santé est la miniaturisation des capteurs et de leurs instrumentations associées pour les rendre non-invasifs, portables par le patient et ainsi adaptés aux mesures ambulatoires en conditions réelles, ou appelées aussi écologiques . Le manuscrit présente la conception et la réalisation d un système électronique miniaturisé ambulatoire ( Hématron), permettant de réaliser un monitoring continu, en temps réel de la conductivité thermique tissulaire qui est l image de la microcirculation dans les capillaires. La première expérimentation effectuée a pour l objectif de confronter le système Hématron avec un moniteur de fluxmétrie laser Doppler, au cours d une étude destinée à évaluer le confort thermique chez l homme. Ainsi, une étude d influence de la température de différentes ambiances sur un certain nombre de paramètres de la peau de sujets sains, y compris la microcirculation cutanée, a été réalisée. Les corrélations obtenues entre les variations des deux signaux des deux instrumentations pour les ambiances neutres, chaudes et froides sont présentées. La deuxième expérimentation est consacrée à l étude préliminaire de l effet global des bas médicaux de compression sur la microcirculation cutanée des membres inférieurs de sujets sains. Grâce à l instrumentation ambulatoire, la microcirculation a pu être évaluée de façon continue pour différentes postures des sujets : allongée, assise, débout et en marche, et ce, pour des différentes classes de bas de compression (I, II, et III). Cette étude a permis d améliorer la compréhension de l effet de ces bas sur les sujets sains.The microcirculation consists of a vascular network that includes arterioles, venules and capillaries. Skin microcirculation is an important physiological parameter for advanced clinical applications such as Raynaud's syndrome or the prevention of ulcers. Many non-ambulatory methods were developed to measure blood microcirculation. The current trend in the field of health technology is the miniaturization of sensors and their associated instrumentation to make them non-invasive, portable by the patient and adapted to ambulatory measurements in time real, or also known as ecological . The manuscript presents the design and the realization of an ambulatory miniaturized electronic system ( Hematron), to achieve continuous monitoring of the effective thermal conductivity in real-time that is the image of the microcirculation in the capillaries. The first experimentation was performed to compare the Hematron system with a laser Doppler flowmetry monitor, during a study which aims to evaluate thermal comfort in humans. A study of the effects of different temperature environments on a group of skin parameters of healthy subjects, including the cutaneous microcirculation, was performed. Correlations between changes in the two signals of both instrumentations for neutral, hot and cold temperatures are presented. The second experimentation is aimed to a preliminary study of the global effect of medical compression stockings on the cutaneous microcirculation of the lower extremities of healthy subjects. Thanks to the ambulatory instrumentation, the microcirculation has been measured continuously for different postures of subject: lying, sitting, standing and walking, and this for different classes of compression stockings (I, II, and III). This study has improved the understanding of the effect of these stockings on healthy subjects.VILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

Design and evaluation of a novel technology for ambulatory monitoring of bruxism events

International audienceBruxism is a widespread phenomenon whose diagnosis is usually made from non reliable, self-evaluation of the patient on one hand, and clinical signs whose absence does not mean absence of bruxism on the other hand. Different methods have been used in research setting for the assessment of bruxism such as portable electromyography but currently there exists no reliable method for the diagnosis of bruxism at home. In this paper, the hardware and software architecture of a complete ambulatory system, enabling long term monitoring of bruxism by measuring clenching/grinding forces of the patient is presented. The results of the tests conducted in vitro to evaluate the sensor's response are also presented. In vivo tests exhibited good correlation with an electromyography of the masseter muscle. With a maximum thickness of 2 mm, the discomfort for the patient is reduced and corresponds nearly to the usual thickness of an occlusal splint. This inductively rechargeable instrumented splint enables a long-term use over different periods and clenching/grinding data can be retrieved locally or transmitted wirelessly via WiFi, on a secured server, for further analysis

Design and Optimization of an Autonomous, Ambulatory Cardiac Event Monitor

International audienceWearable sensors for health monitoring can enable the early detection of various symptoms, and hence rapid remedial actions may be undertaken. In particular, the monitoring of cardiac events by using such wearable sensors can provide real-time and more relevant diagnosis of cardiac arrhythmias than classical solutions. However, such devices usually use batteries, which require regular recharging to ensure long-term measurements. We therefore designed and evaluated a connected sensor for the ambulatory monitoring of cardiac events, which can be used as an autonomous device without the need of a battery. Even when using off-the-shelf, low-cost integrated circuits, by optimizing both the hardware and software embedded in the device, we were able to reduce the energy consumption of the entire system to below 0.4 mW while measuring and storing the ECG on a non-volatile memory. Moreover, in this paper, a power-management circuit able to store energy collected from the radio communication interface is proposed, able to make the connected sensor fully autonomous. Initial results show that this sensor could be suitable for a truly continuous and long-term monitoring of cardiac events

Conception et développement de capteurs et vêtements intelligents pour le suivi et la protection des pompiers (mesures thermiques non-invasives ambulatoires)

Les secouristes, par la nature et le cadre de leurs missions, interviennent en environnement à risque et mettent parfois leur santé en danger. Afin de minimiser ce risque, de nouveaux Equipements de Protection Individuelle (veste, tee-shirt et bottes) ont été conçus par un consortium européen de 23 partenaires réunis autour du programme de recherche ProeTEX. Ces travaux de thèse s inscrivent dans le cadre de ce projet et ont pour objectif de développer un système de monitoring ambulatoire des paramètres thermiques du pompier qui sera intégré aux vêtements intelligents destinés aux secouristes. L intérêt de cette intégration est le prépositionnement des capteurs afin de réduire le temps de préparation du secouriste. La surveillance s opère à deux niveaux : l interface Homme-environnement et le corps. Afin d évaluer le risque thermique encouru, les paramètres faisant l objet d un suivi sont : la température interne, mesurée depuis le tee-shirt, et la température externe et le flux thermique, mesurés dans la veste. Ces paramètres permettent d apprécier la contrainte thermique imposée par l environnement et l état de santé du pompier. Deux méthodes de mesure des paramètres thermiques dans la veste ont été développées. Le projet a abouti au développement de prototypes fonctionnels dont les performances ont été attestées en centre de validation. Des tests ont été conduits en laboratoire et en conditions extrêmes sur le terrain à la Brigade de Sapeurs-Pompier de Paris et au International Firefighting, Survival and Rescue at Sea Training Center de Pavie, Italie, pour démontrer la fonctionnalité des EPI en conditions réelles.Rescuers, within the framework of their missions, operate in hazardous condition and sometimes put their health at risk. To minimize this risk, new personal protective equipment (jacket, t-shirt and boots) were designed by a 23 European partners consortium within the research program ProeTEX. This thesis is part of this project and aims to develop an ambulatory monitoring system for firefighters thermal parameters; It will be integrated into smart clothes for rescuers. Monitoring is taking place at two levels: Human-environment interface and body. To evaluate the thermal hazard involved, the parameters being monitored are: internal temperature, measured from the tee-shirt and external temperature and heat flux, in the jacket. These parameters are used to assess heat stress imposed by the environment and the health status of the fire-fighter. Two methods of measurement of thermal parameters in the jacket were developed. The project resulted in the development of functional prototypes whose performances have been vouched in validation center. Tests took place in the laboratory and during field trails in extreme conditions.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocVILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

Capteurs cutanés non invasifs et monitoring continu pour l'objectivation du confort d'assise et la prévention de l'escarre

Le confort d assise, phénomène complexe, nécessite pour son objectivation toute une batterie de concepts et de dispositifs complémentaires depuis les mesures physiques jusqu aux réactions conscientes et inconscientes des systèmes nerveux centraux et périphérique. L impact sociétal du confort d assise et de la prévention de l escarre s étend sur un champ de plus en plus large : handicapés moteur en assise permanente (pathologique ou accidentelle), nombre en croissance rapide des personnes âgées dépendantes, assise en voiture, longs trajets d avions, engins de chantier, ou fauteuils de bureau L objectivation du confort d assise et du confort en général est complexe et multidisciplinaire s articulant autour de trois composantes : la mesure des pressions d interface sur la matière molle, principale constituant du corps humain par des capteurs, à matrice active souple à recherche de pression d équilibre, la mesure et l étude de la microcirculation cutanée par capteur non invasif, l Hematron, et enfin l étude objective du stress ressenti par le patient, par l évaluation des réactions non conscientes du SNA (Système Nerveux Autonome) à l aide d une méthodologie s appuyant sur des mesures non invasives. Ce travail de thèse pose les bases d une méthode originale pour objectiver le confort d assise. Elle est composée de deux parties indissociables et en symbiose : la composante intrinsèque concernant l évaluation et la mesure de l activation de la branche sympathique du système nerveux autonome associée au stress ressenti par le sujet et la composante extrinsèque concerne l évaluation et la mesure de l actimétrie d assise, par capteur électropneumatique numérique original pour l étude de la réponse comportementale du corps humain au stress d assise. Ces travaux de recherche trouvent leur aboutissement dans la conception et la réalisation opérationnelle d une instrumentation spécifique et la méthodologie d analyse pour la délivrance d informations pour : le diagnostic précoce, le traitement préventif et les informations a finalités décisionnelles.Sitting comfort objectivation requires lot of complementary devices and concepts from physical measurements to central and peripheral nervous systems conscious and unconscious reactions. Sitting comfort investigation and pressure ulcer prevention societal impact extends on an increasingly broad field: handicapped (pathological or accidental), exponential growth in the old dependent people number, car seats, long ways of planes, machines of building seats, or office armchairs... The sitting comfort objectivation and comfort in general is complex and multidisciplinary articulating itself around three components: the interface pressure measurement on the soft, principal matter constituting human body, using flexible active matrix sensors, the measurement and the skin blood flow measurement using non invasive sensor, Hematron, and finally stress felt by the patient evaluation using ANS (Autonomous Nervous system) non conscious reactions evaluation using a non invasive measurements methodology. Our proposal aims to provide an original method to objectify the sitting comfort. It is made up of two symbiosis different parts: in one hand the intrinsic component concerning the evaluation and the measurement of the sympathetic autonomous nervous system activation associated the subject stress felt, in the other hand the extrinsic component relates to the sitting actimetry evaluation and measurement using original numerical electropneumatic sensor specific to the human behavioural sitting stress response study. These research tasks succeed to the design and the realization of a specific operational devices and analysis methodology and providing information for: early diagnosis, preventive treatment and decisional purposes.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Design and Optimization of an Autonomous, Ambulatory Cardiac Event Monitor

International audienceWearable sensors for health monitoring can enable the early detection of various symptoms, and hence rapid remedial actions may be undertaken. In particular, the monitoring of cardiac events by using such wearable sensors can provide real-time and more relevant diagnosis of cardiac arrhythmias than classical solutions. However, such devices usually use batteries, which require regular recharging to ensure long-term measurements. We therefore designed and evaluated a connected sensor for the ambulatory monitoring of cardiac events, which can be used as an autonomous device without the need of a battery. Even when using off-the-shelf, low-cost integrated circuits, by optimizing both the hardware and software embedded in the device, we were able to reduce the energy consumption of the entire system to below 0.4 mW while measuring and storing the ECG on a non-volatile memory. Moreover, in this paper, a power-management circuit able to store energy collected from the radio communication interface is proposed, able to make the connected sensor fully autonomous. Initial results show that this sensor could be suitable for a truly continuous and long-term monitoring of cardiac events

A Portable Heat Flux Sensor

Sept. 2014International audienceno abstrac

Gouttière occlusale intelligente pour l’étude et le diagnostic du bruxisme

International audienc

Resonant force sensor using a PLL electronic

International audienceThe working principle of resonant force sensors with double ended tuning forks (DETF) consists of measuring one of the resonant frequencies of the vibrating beams which depend on the force applied in the beams. Although the principle is simple, its practical application presents some problems. The principal difficulties in the design of such a structure lie in two principal points dealing with the mounting of the DETF on its support and with the mechanical resistance of the structure. In order to approach the ideal structure, the proposed force sensor is based on a DETF directly machined in a metallic circular plate. The force to be measured is applied on the plate by using a tube. The sensor has been designed using finite element simulations. An electronic circuit including both analog PLL and logic circuitry parts has been developed for frequency shift measurement, dedicated to this sensor. A prototype has been realized and tested which gives promising results; the principal technical features of the prototype are reported