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Use of rescue noninvasive ventilation for post-extubation respiratory failure
No full textInternational audienceBackground: Robust evidence supports the use of preemptive non-invasive ventilation (NIV) after extubation in selected high-risk patient cohorts. In contrast, current guidelines discourage the use of NIV as a rescue therapy for respiratory failure that develops later after extubation, based on earlier studies indicating a potential increase in hospital mortality due to delayed reintubation. Nonetheless, NIV continues to be employed in this setting. We conducted a post-hoc analysis of a randomized trial to assess the clinical outcomes of rescue NIV for post-extubation respiratory failure.Methods: In this post-hoc analysis of a randomized trial comparing high-flow with Venturi mask oxygen in hypoxemic patients after extubation, we included those who developed post-extubation respiratory failure according to prespecified criteria; patients who received rescue NIV per physician’s decision were compared to those who received direct re-intubation. Criteria for re-intubation during NIV were prespecified. Odds ratio after inverse probability of treatment weighting and posterior probabilities by Bayesian regression are reported.Results: Among 494 extubated patients, 147 developed respiratory failure while receiving oxygen therapy, occurring at a median of 37 h [IQR 13–85] after extubation: 83 (57%) were treated with rescue NIV and 64 (43%) received immediate re-intubation. The rate of NIV failure was 58%, without differences between patients with hypoxemic respiratory failure and those with hypercapnia and/or respiratory distress (60% vs. 56%, p = 0.82). In the weighted cohort, the use of rescue NIV, compared to direct re-intubation, was associated with lower intensive care unit mortality (adjusted odds ratio = 0.31 [95%CI: 0.12–0.82], p = 0.019) and similar hospital mortality (adjusted odds ratio = 1.01 [95%CI: 0.43–2.33], p = 0.99). The posterior probability that NIV reduced intensive care unit mortality was > 90% across all priors. The posterior probability that NIV did not increase hospital mortality was 44% under a noninformative prior, 47% under a skeptical prior, and 39% under a pessimistic prior.Conclusion: Rescue NIV for post-extubation respiratory failure is associated with high failure rates; however, when applied with well-defined criteria for reintubation, it does not appear to be clearly associated with increases in hospital mortality. A randomized trial to re-evaluate the efficacy of rescue NIV for post-extubation respiratory failure is warranted.Clinical trial registration: Registered at clinicaltrials.gov (NCT02107183) on April 8th, 2014
Le travail du lien dans la clinique de l’autisme et du bébé en détresse : le rôle de la présence de l’analyste
No full textThis clinical research focuses on the challenges posed by the psychoanalytic treatment of severely autistic children and babies in great distress, whose difficulties with relationships and language place limits on traditional frames of reference. The complexity of these clinical situations demands a transformation of practice and knowledge, encouraging the creation of new clinical systems to deal with suffering that is extreme, unrepresentable, unrelated, and that challenges the archaic. The study focuses on four central themes at the heart of the transferential dimension: the bond, the body, the rhythm and the presence of the analyst, all of which are crucial to understanding and supporting this suffering experienced 'outside the psyche'. This research proposes to broaden the psychoanalytic technique by incorporating innovative methods such as body techniques and the use of a video camera, while emphasising the importance of working together to think about and tackle this archaic clinic. Inspired by Fernand Deligny's approach of recognising, supporting and elaborating the barely perceptible elements in the clinical encounter, this technical device becomes a central organiser of the encounter in these complex situations. The research is based on an in-depth analysis of an inaugural case, which reveals the paths and events of an unexpected clinical encounter with a severely autistic child. Other clinical vignettes are then used to test our hypotheses and to illustrate the theoretical concepts and techniques developed. The analysis of the cases is part of a collective elaboration process, which guarantees the rigour and validity of the conclusionsCette recherche clinique se concentre sur les défis soulevés par la prise en charge psychanalytique d'enfants autistes sévères et de bébés en grande souffrance, dont les difficultés de lien et de langage posent des limites aux cadres de référence traditionnels. La complexité de ces situations cliniques nécessite une transformation des pratiques et des savoirs, ce qui encourage la création de nouveaux dispositifs cliniques pour aborder une souffrance qui se révèle extrême, se situant dans un registre non représentable et hors relation, qui renvoie à la question de l’archaïque. La réflexion articule quatre axes centraux qui sont au cœur de la dimension transférentielle : le lien, le corps, le rythme et la présence de l'analyste, éléments cruciaux pour la compréhension et l'accompagnement de cette détresse qui est vécue « hors psyché ». Cette thèse propose ainsi d'élargir la technique psychanalytique en y intégrant des méthodes innovantes, telles que des techniques du corps et l'utilisation d’une caméra vidéo, tout en soulignant l'importance d'un travail collectif pour penser et aborder cette clinique archaïque. S'inspirant de l'approche de Fernand Deligny pour repérer, soutenir et élaborer les éléments à peine perceptibles dans la rencontre clinique, ce dispositif technique devient un organisateur central de la rencontre dans ces situations complexes. La recherche repose sur l'analyse approfondie d'un cas inaugural, qui révèle les pistes et les événements d'une rencontre clinique inattendue avec un enfant autiste sévère. D'autres vignettes cliniques permettront ensuite de mettre à l'épreuve les hypothèses et illustrer les concepts théoriques et techniques élaborés. L'analyse des cas s'inscrit dans un travail collectif d'élaboration, garantissant ainsi la rigueur et la validité des conclusions
Correction to: Hypertensive acute heart failure: a critical perspective on definition, epidemiology, pathophysiology, and prognosis—a narrative review: a joint session with the Romanian Society of Cardiology (part II)
No full textInternational audienceNo abstract availabl
Croyances sur la contrôlabilité des difficultés psychologiques et santé mentale : quelles populations cibler dans l’enseignement supérieur français ?
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L'élaboration des actions collectives par les requérants : de la stratégie contentieuse au contentieux stratégique
No full textRéf : RDP juin 2025, n° RDP200s4.International audienceLe développement récent des actions collectives s'est accompagné d'innovations contentieuses. Le présent article propose une lecture de ce phénomène centrée sur les requérants dans une perspective stratégique. Il s'agit d'apprécier la manière dont les requérants contribuent, par l'usage qu'ils font des voies de droit collectives, à façonner le contentieux administratif.PlanI – Faire émerger une stratégie contentieuseA – Un large répertoire d’actions contentieuses entre les mains des requérantsB – Le choix des modalités d’action par les requérantsII – Construire un contentieux stratégiqueA – L’invention du contentieux structurelB – La transformation de l’action en une interpellatio
Ultrasound stimulation of bone cells: 3D finite-element model of acoustic streaming around osteocytes
No full textInternational audienceIntroductionUltrasound (US) stimulation of bone remodeling remains an open question as the underlyingmechanisms involved are still poorly understood. Among the possible hypotheses, thepropagation of ultrasonic waves (US) in bone tissue could generate acoustic streaming (AS)resulting in fluid shear stress exerted on the wall of osteocytes known as the mechanosensitiveconductors of bone remodeling. Osteocytes are dendritic cells surrounded by a viscouspericellular fluid (PCF), ubiquituous in the bone extra-cellular matrix (ECM) forming acomplex micrometric 3D network called the lacuno-canalicular network (LCN).This paper investigates the interaction of US with the osteocyte dendrite (OD) confinedin a canaliculus, as it is considered as the most mechanosensitive part of the cell. The aimis to explore the relevance of taking into account the irregular 3D shapes of the canaliculusand dendrite in terms of mechanical sollicitations induced by US stimulation.Material & Methods∗Speakersciencesconf.org:esmc2025:592919From images (FIB-SEM imaging ”slice and view” in BSE mode (Gianuzzi 2004), FEI HeliosNanoLab 660, pixel size 16.78 × 16.78 × 20 nm3), a realistic 3D geometry of a canaliculus ofrabbit cortical bone is reconstructed and implemented in the Finite-Element software ComsolMultiphysics (v. 6.2). The geometry of the dendrite inside the canaliculus (not accessibleby imaging) is deduced from the canaliculus wall geometry.The acoustic properties of the cell dendrite and of the PCF are similar to those of water,except that the viscosity of the PCF is supposed to be 10 times higher than water dynamicviscosity (μwater=0.65.10-3 Pa.s).To mimic the US stimulation od bone cells inside the LCN, a first order oscillating velocityU1 is imposed along the ECM/PCF interface under the form of a harmonic acousticwave at frequency f of 1 MHz with an amplitude of displacement d0 propagating in the USpropagation direction: U1(f) = i2πfd0ex.The acoustic streaming is a second-order (non-linear) acoustic effect which results in a steadyflow. In order to investigate the acoustic streaming induced by US stimulation inside thePCF, we need to solve the second-order Navier-Stokes equations obtained by the perturbationmethod.In Comsol Multiphysics, the Thermoviscous Acoustics module (in frequency domain) is usedto resolve the first order acoustic field which provides the source term for the second orderequation implemented in the Laminar Flow module.From the acoustic streaming velocity (time-averaged second-order term) thus obtained, theresulting wall shear stress (WSS) applied at the PCF/process interface is calculated.Results & DiscussionThe WSS is plotted along the interface PCF/OD. The values are compared to those obtainedfor idealized 3D-geometries (annular tube) deduced from the realistic one and to theresults obtained in 2D cross-sections as previously presented in (Baron 2023).We investigate how canaliculus and dendrite geometries could have an influence on theUS-induced PCF flow. Finally, the quantification of the WSS induced by acoustic streamingis questioned in regard of stress levels that can trigger a biological response (Weinbaum 1994).Keywords: acoustic streaming; wall shear stress, osteocyte; mechanotransduction; FEmodel; FIB-SEM.Aknowledgements: This work was supported by the French National Research Agency,ANR-23-CE51-0018 and ANR-22-CE51-0038.ReferencesBaron C, Doveri E, Jodlowski P., Lasaygues P, Guivier-Curien C. Acoustic streaming inbone pericellular fluid under ultrasound stimulation. CMBBE, 2023, 26. hal-04298077.Giannuzzi, L. A. (Ed.). Introduction to focused ion beams: instrumentation, theory, techniquesand practice. Springer Science & Business Media, 2004.Weinbaum S, Cowin SC, Zeng Y. A model for the excitation of osteocytes by mechanicalloading-induced bone fluid shear stresses. J Biomech. 27(3):339-60
Engineered micro-structured biomimetic material for modelling the outer blood-retinal barrier
No full textInternational audienceThe outer blood-retinal barrier (oBRB) is compromised in several retinal pathologies, such as age-related macular degeneration affecting over 200 million people worldwide. This 200-350 μm thick tissue includes the retinal pigment epithelium (RPE), the Bruch's membrane, and the vascularized choroid supplying the outer retina. Degeneration of the RPE and/or choroid leads to photoreceptor loss and, ultimately, blindness. Current in vitro co-culture oBRB models developed to better understand the diseases and to propose therapeutic alternatives are often simplistic, focusing on 2D cultures, or face limitations including non-physiological dimensions or low throughput.This study presents an innovative scaffold-driven approach to model the oBRB using a polysaccharide membrane engineered by freeze-drying. Our specific protocol allowed to mimic the oBRB structure, within physiological dimensions, generating a non-porous surface to culture the hiPSC-derived RPE monolayer, and an internal 3D porous structure for the choroidal network. Results showed that the inner porous structure promoted physiological self-organization of endothelial cells and pericytes. Our single-piece functional material allowed the cultivation of both RPE and choroidal compartments in close proximity, favoring cellular interactions, while maintaining them in their designated locations. This cyto-compatible, easy-to-use, and off-the-shelf membrane, produced at large amounts and low costs, provides a physiologically relevant biomaterial for oBRB tissue modelling.</div
Challenges and limitations in developing of a new maxillary standardized rat alveolar bone defect model to study bone regenerative approaches in oral and maxillofacial surgery
No full textInternational audienceInnovative biomaterials are increasingly being investigated for guided bone regeneration (GBR) in oral and maxillofacial surgery. However, the development of relevant preclinical models still need to be consiedered. This study aimed to propose a standardized and reproducible maxillary bone defect model in rats that could be relevant to evaluate new materials for GBR. Three defect sizes in rat maxillary of 2.8, 3.3, and 4.5 mm in diameter were compared. Bone formation was followed until 12 weeks post-surgery using longitudinal micro-computed tomography and histological analysis. The defect was subsequently filled by an osteoconductive bone substitute (GLYCOBONE), then covered either by a new natural polysaccharide membrane supplemented with hydroxyapatite, or by a commercial collagen membrane (BIO-GIDE). Results showed little spontaneous tissue regeneration for empty defects (bone volume fractions (BVF) below 40% after 12 weeks). The smallest size defect (2.8 mm) was the most reproducible and was thus selected for testing GBR membranes. Defects filled with GLYCOBONE and covered with membranes displayed for both materials accelerated and substantial bone regeneration (with BVF that reached 80% after 12 weeks). Histological sections showed immature bone formation for the empty defects, whereas the defects filled with the GBR membranes highlighted a lamellar structured bone. The polysaccharide membrane was as effective as the commercial collagen membrane to guide bone tissue regeneration. This study provides a step-bystep protocol of a new standardized rat maxillary bone defect model. In line with ethical and financial considerations, this rodent model should be considered as a preliminary level before performing larger animal experiments
Correlates of food insecurity among university students in a disadvantaged socioeconomic area in France
No full textInternational audienceBackground and objectivesThe higher education student population is particularly concerned by foodinsecurity (FI), although data collected in France is limited and varies dependingon socio-economic contexts. This cross-sectional study aims, 1) to assess theprevalence of FI among university students in a socioeconomically disadvantagedarea, 2) to assess the association of FI with perceived school dropout, and 3) todescribe the socioeconomic, demographic and academic factors, as well as thecooking and eating conditions associated with FI.MethodsAn online survey was conducted (Nov 2022 to Jan 2023) among 5068 students(22% of the university population) enrolled at a university located in a lowsocioeconomic area. FI was assessed using a question with three responsemodalities: not having access to enough food (i.e. quantitative FI); not havingaccess to the desired food (i.e. qualitative FI); having access to enough of thedesired food (i.e. food security). Weighting was calculated (compared to theoverall student population of the university) using gender, study level, field ofstudy, country of high school diploma obtention, and training status. Multivariatemultinomial logistic regression models were used to identify associations between i)FI and school drop-out; ii) socioeconomic and demographic data, academic-relateddata, cooking and eating conditions and FI.ResultsAmong respondents, 60% were women and 21% reported financial difficulties ≥4(out of 5). After weighting, 11% and 35% reported quantitative and qualitative FI,respectively. In multivariable analyses, students reporting quantitative orqualitative FI were more likely to report school dropout than people reporting foodsecurity. Besides, reporting financial difficulties, living in a collective residence, nothaving cooking facilities at home, being an undergraduate, having obtained highschool diploma abroad, not cooking frequently, relying on food aid and eating aloneregularly were positively associated with both quantitative and qualitative FI.Being a man was associated only with quantitative FI. (P<0.0001)ConclusionsThis study reported a concerning prevalence of FI among students in adisadvantaged socioeconomic area. FI was associated with greater perceivedschool dropout, which may further increase socioeconomic inequalities. Bothstructural (e.g. socioeconomic status, accommodation type) and individual-level(e.g. cooking and eating conditions) factors were found to be associated with FI.These findings provide insight into the characteristics of students more likely toexperience FI and to be the target of interventions
Machine Learning-Based Netmob25 Mobility Model for Network Simulators
No full textInternational audienceUser mobility pattern has a great impact on mobile network performances. In network simulation, researchers need tools to generate realistic user trajectories. In this paper, we propose to use Variational Autoencoders to capture the characteristics of the Netmob25 mobility dataset. This machine learning model is then used to build a new mobility model in the NS3 network simulator to generate a number of trajectories in different types as needed