Extracorporeal membrane oxygenation (ECMO) is widely used for children treated for refractory respiratory failures or refractory cardiogenic shock. Its duration depends on organ functions recovery. ...Weaning is decided using macro-circulatory tools, but microcirculation is not well evaluated. Sidestream dark-field video imaging is used to assess the perfusion of the sublingual microvascular vessels. The aim of this study was to assess the predictive value of microcirculatory indices in ECMO weaning.
This prospective monocentric study examined pediatric patients at Trousseau Hospital between March 2017 and December 2020. The study included all patients from 35 weeks of gestational age to 18 years old who were treated with ECMO. Children were divided into two groups: one with stability after weaning and the other with instability after weaning. We collected clinical and biological data, ventilation parameters, extracorporeal membrane oxygenation parameters, and drugs used at admission and after the weaning test. Microcirculations videos were taken after weaning trials with echocardiography and blood gas monitoring.
The study included 30 patients with a median age of 29 days (range: 1-770 days) at admission, including 18 patients who received venoarterial ECMO (60%). There were 19 children in the stability group and 11 in the instability group. Macrocirculatory and microcirculatory indices showed no differences between groups. The microvascular flow index was subnormal in both groups (2.3 (1.8-2.4) and 2.3 (2.3-2.6), respectively; p = 0.24). The microvascular indices were similar between cases of venovenous and venoarterial ECMO and between age groups.
Microcirculation monitoring at the weaning phase did not predict the failure of ECMO weaning.
In the framework of safe underground storage of radioactive waste in low-permeability layers, it is essential to evaluate the mobility of deep groundwaters over timescales of several million years. ...On these timescales, the environmental evolution of a repository should depend upon a range of natural processes that are primarily driven by climate and geomorphologic variations. In this paper, the response of the Paris basin groundwater system to variations in its hydrodynamic boundary conditions induced by past climate and geodynamic changes over the last five million years is investigated.
A three-dimensional transient modelling of the Paris basin aquifer/aquitard system was developed using the code NEWSAM (Ecole des Mines de Paris, ENSMP). The geometry and hydrodynamic parameters of the model originate from a basin model, NEWBAS (ENSMP), built to simulate the geological history of the basin. Geomorphologic evolution is deduced from digital elevation model analysis, which allows to estimate river-valley incision and alpine surrection. Climate forcing results from palaeoclimate modelling experiments using the LMDz atmospheric general circulation model (Institut Pierre Simon Laplace) with a refined spatial resolution, for the present, the Last Glacial Maximum (21
ka) and the Middle Pliocene Warmth (∼3
Ma). The water balance is computed by the distributed hydrological model MODSUR (ENSMP).
Results about the simulated evolution of piezometric heads in the system in response to the altered boundary conditions are presented, in particular in the vicinity of ANDRA’s Bure potential repository site within the Callovo-Oxfordian argillaceous layer. For the present, the comparison of head patterns between steady state and time dependent simulation shows little differences for aquifer layers close to the surface but suggests a transient state of the current system in the main aquitards of the basin and in the deep aquifers, characterized by abnormally low fluid potentials. The dependence of the boundary-induced transient effects on the hydraulic diffusivity is illustrated by means of a sensitivity study.
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