Evaluation de l'adaptation à la ventilation non invasive chez des patients atteints d'insuffisance respiratoire chronique

A decrease in the efficiency of the ventilatory mecanic leads to chronic respiratory failure. So far, the treatment that has been priviledged consists in a noninvasive ventilation, used mostly at night during sleep time. The aim of this work is to study the impact that the noninvasive ventilation has on the organism, which means studying its impact on the quality of breath as well as the quality of sleep. The mechanisms underlying patient-ventilator interactions and the influences of these mechanisms are considered and quantified. To do so, two studies based on polysomnography were carried out. During a preliminary retrospective study, synoptics were made which allowed us to have a global visualization of the events occuring during the night, by the simultaneous representation of the recording variables during the polysomnography. We were then able to quantify the connections between the various patient-ventilator asynchronisms and the non-intentional leaks. Four different patient-ventilator types of interactions could thus be highlighted. A second study, prospective this time, was carried out on how patients who suffer from chronic ventilatory failure can adapt themselves to non-invasive ventilation during the initiation period. This study was based on the analysis of three polysomnographies : one was made during the first night at the hospital under spontaneous breathing, the second one was made during the second night under noninvasive ventilation and the third one was made15 days later. An individual analysis could then be carried out, based on the interpretation of the synoptics of each patient, and a global analysis was performed as well through a statistic approach. A Shannon entropy calculated on recurrence plot, was also used to estimate the quality of sleep. During the initiation of long-term noninvasive ventilation, ventilatory parameters (oxymetry and capnography) were improved, patients showed a progressive increase of the time spent in REM sleep and the sleep fragmentation was reduced thanks to a correction of obstructive sleep apneas. Under noninvasive ventilation, cardiac variability, estimated with a Shannon entropy based on a symbolic dynamic, was significantly reduced. Only a few effects of the asynchronisms on ventilation quality were noticed in this study.Résumé.La diminution de l’efficacité de la mécanique ventilatoire entraîne une insuffisance respiratoire chronique. A ce jour, le traitement privilégié consiste en une assistance ventilatoire non invasive, essentiellement utilisée la nuit. L’objectif de ce travail est d’étudier les influences de la ventilation non invasive sur l’organisme non seulement du point de vue de la qualité de la respiration, mais aussi sur la qualité du sommeil. Les mécanismes sous-jacents aux interactions patient-ventilateur et leurs influences sont pris en compte et quantifiés. Pour cela, deux études basées sur des polysomnographies ont été effectuées. Lors d’une première étude rétrospective, des synoptiques permettant une visualisation globale des événements au cours de la nuit par la représentation simultanée des variables enregistrées lors de la polysomnographie ont été construits. Ensuite, nous avons quantifié les relations entre les différents asynchronismes patient-ventilateur et les fuites non intentionnelles. Quatre types d’interactions patient-ventilateur ont ainsi pu être mis en évidence. Une seconde, prospective, a été conduite sur l’adaptation des patients à la ventilation non invasive lors de sa mise en place chez des patients atteints d’insuffisance respiratoire chronique. Reposant sur trois polysomnographies respectivement réalisées lors de la première nuit à l’hôpital en ventilation spontanée, lors de la deuxième à l’hôpital sous assistance ventilatoire non invasive et lors d’une troisième nuit à l ?hôpital, 15 jours après l’appareillage. Une analyse individuelle a été effectuée par l’interprétation des synoptiques de chacun des patients, et une analyse globale a été effectuée par une approche statistique. Une entropie de Shannon, calculée à partir de diagrammes de proche-retour, a également été utilisée pour estimer la qualité du sommeil. La mise en place de la ventilation se traduit par une amélioration des paramètres ventilatoires (oxymétrie et capnographie), une amélioration voire une restauration du temps passé en sommeil paradoxal, et une diminution de la fragmentation du sommeil par la correction des apnées obstructives. Sous ventilation, la variabilité cardiaque, estimée à partir d’une entropie de Shannon calculée sur la base d’une dynamique symbolique, diminue significativement. Peu d’effets des asynchronismes sur la qualité de la ventilation ont été notés au cours de cette étude

An Ultrasonic Contactless Sensor for Breathing Monitoring

International audienceThe monitoring of human breathing activity during a long period has multiple fundamental applications in medicine. In breathing sleep disorders such as apnea, the diagnosis is based on events during which the person stops breathing for several periods during sleep. In polysomnography, the standard for sleep disordered breathing analysis, chest movement and airflow are used to monitor the respiratory activity. However, this method has serious drawbacks. Indeed, as the subject should sleep overnight in a laboratory and because of sensors being in direct contact with him, artifacts modifying sleep quality are often observed. This work investigates an analysis of the viability of an ultrasonic device to quantify the breathing activity, without contact and without any perception by the subject. Based on a low power ultrasonic active source and transducer, the device measures the frequency shift produced by the velocity difference between the exhaled air flow and the ambient environment, i.e., the Doppler effect. After acquisition and digitization, a specific signal processing is applied to separate the effects of breath from those due to subject movements from the Doppler signal. The distance between the source and the sensor, about 50 cm, and the use of ultrasound frequency well above audible frequencies, 40 kHz, allow monitoring the breathing activity without any perception by the subject, and therefore without any modification of the sleep quality which is very important for sleep disorders diagnostic applications. This work is patented (patent pending 2013-7-31 number FR.13/57569). OPE

Is type 1 diabetes a chaotic phenomenon?

A database of ten type 1 diabetes patients wearing a continuous glucose monitoring device has enabled to record their blood glucose continuous variations every minute all day long during fourteen consecutive days. These recordings represent, for each patient, a time series consisting of 1 value of glycaemia per minute during 24 hours and 14 days, i.e., 20,160 data point. Thus, while using numerical methods, these time series have been anonymously analyzed. Nevertheless, because of the stochastic inputs induced by daily activities of any human being, it has not been possible to discriminate chaos from noise. So, we have decided to keep only the 14 nights of these ten patients. Then, the determination of the time delay and embedding dimension according to the delay coordinate embedding method has allowed us to estimate for each patient the correlation dimension and the maximal Lyapunov exponent. This has led us to show that type 1 diabetes could indeed be a chaotic phenomenon. Once this result has been confirmed by the determinism test, we have computed the Lyapunov time and found that the limit of predictability of this phenomenon is nearly equal to half the 90-minutes sleep-dream cycle. We hope that our results will prove to be useful to characterize and predict blood glucose variations

The cost-effectiveness of domiciliary non-invasive ventilation in patients with end-stage chronic obstructive pulmonary disease:a systematic review and economic evaluation

Background: Chronic obstructive pulmonary disease (COPD) is a chronic progressive lung disease characterised by non-reversible airflow obstruction. Exacerbations are a key cause of morbidity and mortality and place a considerable burden on health-care systems. While there is evidence that patients benefit from non-invasive ventilation (NIV) in hospital during an acute exacerbation, evidence supporting home use for more stable COPD patients is limited. In the UK, domiciliary NIV is considered on health economic grounds in patients after three hospital admissions for acute hypercapnic respiratory failure. Objective: To assess the clinical effectiveness and cost-effectiveness of domiciliary NIV by systematic review and economic evaluation. Data sources: Bibliographic databases, conference proceedings and ongoing trial registries up to September 2014. Methods: Standard systematic review methods were used for identifying relevant clinical effectiveness and cost-effectiveness studies assessing NIV compared with usual care or comparing different types of NIV. Risk of bias was assessed using Cochrane guidelines and relevant economic checklists. Results for primary effectiveness outcomes (mortality, hospitalisations, exacerbations and quality of life) were presented, where possible, in forest plots. A speculative Markov decision model was developed to compare the cost-effectiveness of domiciliary NIV with usual care from a UK perspective for post-hospital and more stable populations separately. Results: Thirty-one controlled effectiveness studies were identified, which report a variety of outcomes. For stable patients, a modest volume of evidence found no benefit from domiciliary NIV for survival and some non-significant beneficial trends for hospitalisations and quality of life. For post-hospital patients, no benefit from NIV could be shown in terms of survival (from randomised controlled trials) and findings for hospital admissions were inconsistent and based on limited evidence. No conclusions could be drawn regarding potential benefit from different types of NIV. No cost-effectiveness studies of domiciliary NIV were identified. Economic modelling suggested that NIV may be cost-effective in a stable population at a threshold of £30,000 per quality-adjusted life-year (QALY) gained (incremental cost-effectiveness ratio £28,162), but this is associated with uncertainty. In the case of the post-hospital population, results for three separate base cases ranged from usual care dominating to NIV being cost-effective, with an incremental cost-effectiveness ratio of less than £10,000 per QALY gained. All estimates were sensitive to effectiveness estimates, length of benefit from NIV (currently unknown) and some costs. Modelling suggested that reductions in the rate of hospital admissions per patient per year of 24% and 15% in the stable and post-hospital populations, respectively, are required for NIV to be cost-effective. Limitations: Evidence on key clinical outcomes remains limited, particularly quality-of-life and long-term (> 2 years) effects. Economic modelling should be viewed as speculative because of uncertainty around effect estimates, baseline risks, length of benefit of NIV and limited quality-of-life/utility data. Conclusions: The cost-effectiveness of domiciliary NIV remains uncertain and the findings in this report are sensitive to emergent data. Further evidence is required to identify patients most likely to benefit from domiciliary NIV and to establish optimum time points for starting NIV and equipment settings. Future work recommendations: The results from this report will need to be re-examined in the light of any new trial results, particularly in terms of reducing the uncertainty in the economic model. Any new randomised controlled trials should consider including a sham non-invasive ventilation arm and/or a higher- and lower-pressure arm. Individual participant data analyses may help to determine whether or not there are any patient characteristics or equipment settings that are predictive of a benefit of NIV and to establish optimum time points for starting (and potentially discounting) NIV. Study registration: This study is registered as PROSPERO CRD42012003286. Funding: The National Institute for Health Research Health Technology Assessment programme

Repérer, dépister et traiter dès l'école maternelle pour prévenir l'illettrisme

National audienceRepérer, dépister et traiter dès l'école maternelle pour prévenir l'illettrisme NAECK VASSEN ASSOCIATE PROFESSOR MAURITIUS INSTITUTE OF EDUCATION Cette étude présente tout d'abord le contexte de l'école maternelle à Maurice. Ensuite notre propos rendra compte des dispositifs et dispositions mobilisés pour répondre aux orientations évoquées dans le titre de notre communication. Nous proposerons enfin une réflexion sur la pertinence des stratégies mises en oeuvre dès l'école maternelle pour prévenir l'illettrisme. DES DONNÉES GÉNÉRALES SUR LA MATERNELLE À MAURICE A Maurice, l'éducation à la maternelle est d'une durée de deux ans (3 à 5 ans) et les enfants entrent à l'école primaire à cinq ans. La maternelle est payante pour les écoles privées et publiques. Toutefois, les familles bénéficient d'une allocation de 200 roupies par enfant pour leur permettre de payer en partie la dernière année de scolarité en maternelle. Bien que l'école maternelle ne soit pas obligatoire, 85 % des enfants y sont scolarisés dès 3 ans et environ 80 % à quatre ans. Il existe 1115 écoles maternelles dont 181 sont gérées par L'Education Nationale et 934 par le secteur privé (Ministry of Education, Culture and Human Resources, Mauritius, 2008). Il faut noter que les conditions de scolarisation ne sont pas comparables d'une école à l'autre, compte tenu de la diversité des approches pédagogiques et de la disparité matérielle entre les structures d'accueil. LES MATERNELLES DES ÉCOLES ZEP (ZONE D'ÉDUCATION PRIORITAIRE) Fortement influencée par le système français en matière de lutte contre les inégalités scolaires d'origine sociale, l'Ile Maurice a érigé en ZEP un certain nombre de secteurs scolaires sis dans des environnements socio-culturellement pauvres. Cette initiative a été prise sur la base de l'hypothèse que les inégalités scolaires résultent de l'inégalité sociale. L'école aggraverait ensuite ces inégalités pour devenir une institution à plusieurs vitesses. Ces inégalités se cristallisent dans un certain nombre de zones, que l'on peut identifier en raison du profil socio-économique des populations

Quel accompagnement à la construction d'une posture réflexive dans la formation initiale des enseignants du primaire à l'île Maurice

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Repérer, dépister et traiter dès l'école maternelle pour prévenir l'illettrisme

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Quel accompagnement à la construction d'une posture réflexive dans la formation initiale des enseignants du primaire à l'île Maurice

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La psychologie scolaire à Maurice : aide et conseil en direction de l'école et des familles

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Littératie et langues asiatiques : vers une dynamique partenariale CERLI et enseigants

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