Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Impact of soil water content on the overturning resistance of young Pinus Pinaster in sandy soil

Background and aims: The tree resistance to uprooting is crucial to face wind damage in temperate forest. Tree anchorage varies considerably with site conditions, species, and tree age. Only few studies have focused on the influence of the site soil properties on the tree anchorage. With ongoing climate change, the soil hydrologic conditions are changing in Europe due to higher precipitations during winter, with possible higher risk of wind damage in forests.Methods: This study investigates the role of soil hydrology on tree anchorage of Pinus pinaster in sandy soil with a combination of field experiments and simulations. Tree pulling experiments until root-soil system failure were performed for 12 Pinus pinaster of 14 years-old growing in podzol to measure the tree resistance to uprooting M-c for two contrasted soil water conditions. In addition, simulations were conducted to analyze how M-c changes during the progressive wetting of the layered soil. For that purpose, a new model was developed for M-c. This model also includes a sub-model for the shear mechanical strengths of the sandy soil layers and their variation with soil water content. The model was calibrated with different data sets: (1) the M-c-data obtained from the tree pulling experiments performed on 14 years-old Pinus pinaster; (2) the 3D root system architectures of the pulled trees; and (3) the soil shear mechanical strength as function of the soil water content measured in laboratory by direct shear tests and soil water retention curve measurements. After calibration,-calculations were performed when simulating a progressive soil wetting by water table increase or by water saturation front progression.Results: Field-data and simulations show that M-c depends little on soil water content outside the domain of complete soil saturation. Close to saturation, simulations show that M-c decreases drastically up to 40 % of its value. This is specific to sandy soil whose mechanical strength is mainly due to the capillarity forces between grains. As illustrated by simulations, the anchorage resistance results from two components. The first friction component slightly increases with soil water content. The second suction component decreases little with soil water content and drops down at saturation when all the interstitial water in the soil porous network merges.Conclusions: This loss of anchorage resistance at full saturation may increase considerably the risk of wind damage of forest growing in sandy soil as floods increase with climate change in Europe.Réponse de l'arbre aux vents fortsAdaptation sylvicole et économique de l'aménagement forestier au risque ventCOntinental To coastal Ecosystems: evolution, adaptability and governanc

Levels and determinants of pesticide exposure in re-entry workers in vineyards: Results of the PESTEXPO study

International audiencePhysical contact with branches, leaves, fruit or vegetables in previously treated crops is responsible for the transfer of pesticides to the worker's skin in agricultural tasks such as harvesting, pruning, thinning, cutting or sorting. Few studies have documented workers' exposure during re-entry in vineyards. In the PESTEXPO study, we described levels of exposure and analyzed their determinants during re-entry and harvesting in vineyards in the Bordeaux area, France. Between 2002 and 2007, volunteers performing re-entry tasks (N=46 days) or harvesting (N=48 days) after dithiocarbamate or folpet treatment were observed. Detailed information on the tasks was collected and dermal contamination was assessed using patches placed on the skin and hand-washing at the end of each working phase. Daily median contamination was 1 967.7 μl of mixture during re-entry (90(e) percentile: 5 045.3 μl) and 18.7 μl during harvesting (90(e) percentile: 911.4 μl). The type of task was the parameter found to be the most strongly associated with contamination. For re-entry, the highest contaminations were observed during raising of wires and cutting of branches. During the harvest, the contamination was maximal for grape-picking. The delay since the last treatment and the rate of active ingredient per hectare played a role, together with other factors such as meteorological factors, crop and farm characteristics, gloves and clothes. Our results underline the necessity to take into account exposures during re-entry and harvest when considering pesticide exposure, both for epidemiological research and preventive action

Aide à l'évaluation des risques aux postes de travail des radiologues industriels

L'objectif de cet atelier du GT SFRP-COFREND a été de proposer une analyse des risques pour la réalisation future d'études de postes sur les tirs en milieu industriel (nucléaire et hors nucléaire). Le principe retenu a été de réaliser un découpage des différentes phases d'un chantier, en y associant à chaque étape les risques associés. Les examens et contrôles non destructifs (END et CND) sont des activités qui nécessitent une vigilance de tous les instants (Fig. 1) pour : s'assurer de la qualité du travail ; gérer les différents risques dont le risque d'exposition aux rayonnements ionisants ; lutter contre des baisses d'attention liées aux formes de fatigue, aux conditions de travail, aux difficultés d'accès et dans certains cas au travail nocturne, etc. ; gérer les pressions temporelles (audits, surveillances...) ; gérer la co-activité pour éviter d'exposer d'autres professionnels ; gérer le risque lié au milieu de travail (INB, présence de produits dangereux...). Le champ d'étude d'une analyse de risque couvre les métiers, les tâches et activités, les nuisances, et les risques... Le principe par la suite d'une étude de poste sera une approche descriptive et analytique de toutes les composantes de la réalité d'un travail donné, son organisation, son environnement, ses contraintes et moyens d'ajustement (Fig. 2). L'étude de poste s'appuiera sur des méthodes objectives d'observation, d'analyse de risque et de mesure (rapport du groupe de coordination étude de postes médecins du travail EDF). L'objectif de l'étude de poste est de lister l'ensemble des actions à mener pour garantir des conditions d'intervention et de travail acceptables afin de prévenir l'ensemble des risques

Multi-users of a Product: Emergence of Contradictions

Part 4: TRIZ and FunctionsInternational audienceThe use of the product is randomly taken into account in the final phase of the design process, which leads to certain iterations and difficulty in use.Generally, the designer has taken into account customer requirements without really knowing the end user, sometimes our end users.By analyzing the different users, it is a question of measuring the functionality of the product for each of them. The various functional analyses must take into account the needs of all these users. Thus, it is necessary to identify: the expectations and cognitive barriers of each user in a competitive environment and to consider the evolution of the use and performance of the product and its interaction with its users.In this article, it’s about listing the product features for each user case. The different functional analyzes must present the expectations for each use case. Thus, in an order of the product use life cycle, it is necessary to identify the purposes and behaviors of users and the level of constraint of each feature. By comparing the functions between them, it is a question of identifying the contradictions or not that can have an effect on the design of the product. A concrete example (baby car seat), is proposed in this article in order to target the different users from the functions and to identify the contradictions that can be resolved by the TRIZ principle