13,586 research outputs found
Ventilator-Associated Pneumonia and PaO2/FIO2 Diagnostic Accuracy: Changing the Paradigm?
BACKGROUND:
Ventilator-associated pneumonia (VAP) is associated to longer stay and poor outcomes. Lacking definitive diagnostic criteria, worsening gas exchange assessed by PaO2/FIO2 ≤ 240 in mmHg has been proposed as one of the diagnostic criteria for VAP. We aim to assess the adequacy of PaO2/FIO2 ≤ 240 to diagnose VAP.
METHODS:
Prospective observational study in 255 consecutive patients with suspected VAP, clustered according to PaO2/FIO2 ≤ 240 vs. > 240 at pneumonia onset. The primary analysis was the association between PaO2/FIO2 ≤ 240 and quantitative microbiologic confirmation of pneumonia, the most reliable diagnostic gold-standard.
RESULTS:
Mean PaO2/FIO2 at VAP onset was 195 ± 82; 171 (67%) cases had PaO2/FIO2 ≤ 240. Patients with PaO2/FIO2 ≤ 240 had a lower APACHE-II score at ICU admission; however, at pneumonia onset they had higher CPIS, SOFA score, acute respiratory distress syndrome criteria and incidence of shock, and less microbiological confirmation of pneumonia (117, 69% vs. 71, 85%, p = 0.008), compared to patients with PaO2/FIO2 > 240. In multivariate logistic regression, PaO2/FIO2 ≤ 240 was independently associated with less microbiological confirmation (adjusted odds-ratio 0.37, 95% confidence interval 0.15-0.89, p = 0.027). The association between PaO2/FIO2 and microbiological confirmation of VAP was poor, with an area under the ROC curve 0.645. Initial non-response to treatment and length of stay were similar between both groups, while hospital mortality was higher in patients with PaO2/FIO2 ≤ 240.
CONCLUSION:
Adding PaO2/FIO2 ratio ≤ 240 to the clinical and radiographic criteria does not help in the diagnosis of VAP. PaO2/FIO2 ratio > 240 does not exclude this infection. Using this threshold may underestimate the incidence of VAP.info:eu-repo/semantics/publishedVersio
Layout level design for testability strategy applied to a CMOS cell library
The layout level design for testability (LLDFT) rules used here allow to avoid some hard to detect faults or even undetectable faults on a cell library by modifying the cell layout without changing their behavior and achieving a good level of reliability. These rules avoid some open faults or reduce their appearance probability. The main purpose has been to apply that set of LLDFT rules on the cells of the library designed at the Centre Nacional de Microelectronica (CNM) in order to obtain a highly testable cell library. The authors summarize the main results (area overhead and performance degradation) of the application of the LLDFT rules on the cell
Symmetry-induced interference effects in metalloporphyrin wires
Organo-metallic molecular structures where a single metallic atom is embedded
in the organic backbone are ideal systems to study the effect of strong
correlations on their electronic structure. In this work we calculate the
electronic and transport properties of a series of metalloporphyrin molecules
sandwiched by gold electrodes using a combination of density functional theory
and scattering theory. The impact of strong correlations at the central
metallic atom is gauged by comparing our results obtained using conventional
DFT and DFT+U approaches. The zero bias transport properties may or may not
show spin-filtering behavior, depending on the nature of the d state closest to
the Fermi energy. The type of d state depends on the metallic atom and gives
rise to interference effects that produce different Fano features. The
inclusion of the U term opens a gap between the d states and changes
qualitatively the conductance and spin-filtering behavior in some of the
molecules. We explain the origin of the quantum interference effects found as
due to the symmetry-dependent coupling between the d states and other molecular
orbitals and propose the use of these systems as nanoscale chemical sensors. We
also demonstrate that an adequate treatment of strong correlations is really
necessary to correctly describe the transport properties of metalloporphyrins
and similar molecular magnets
Effects of Bose-Einstein Condensation on forces among bodies sitting in a boson heat bath
We explore the consequences of Bose-Einstein condensation on
two-scalar-exchange mediated forces among bodies that sit in a boson gas. We
find that below the condensation temperature the range of the forces becomes
infinite while it is finite at temperatures above condensation.Comment: 10 pages, 2 figure
PRS17 VALIDATION OF THE COPD SEVERITY SCORE FOR USE IN THE SPANISH PRIMARY HEALTH CARE SYSTEM, THE NEREA STUDY: PRELIMINARY RESULTS
Correlation Functions of Complex Matrix Models
For a restricted class of potentials (harmonic+Gaussian potentials), we
express the resolvent integral for the correlation functions of simple traces
of powers of complex matrices of size , in term of a determinant; this
determinant is function of four kernels constructed from the orthogonal
polynomials corresponding to the potential and from their Cauchy transform. The
correlation functions are a sum of expressions attached to a set of fully
packed oriented loops configurations; for rotational invariant systems,
explicit expressions can be written for each configuration and more
specifically for the Gaussian potential, we obtain the large expansion ('t
Hooft expansion) and the so-called BMN limit.Comment: latex BMN.tex, 7 files, 6 figures, 30 pages (v2 for spelling mistake
and added reference) [http://www-spht.cea.fr/articles/T05/174
Weldability of spheroidal graphite ductile cast iron using Ni / Ni-Fe electrodes
[ES] Se establece la soldabilidad de funciones dúctiles de grafito según las características mecánicas alcanzadas, utilizando
un electrodo puro de Ni mientras se compara con uno más económico de Ni-Fe. Diferentes tratamientos térmicos
son propuestos y analizados. El electrodo de Ni puro mostró difusión de grafito desde el material original al cordón de
soldadura, dando como resultado una fase homogénea que mejoró la soldabilidad y redujo la fragilidad. Un pre tratamiento
a 350 °C y un recocido a 850 °C incrementaron la ductilidad y mejoró la soldabilidad.[EN] Weldability of spheroidal graphite ductile cast iron was established using a cheap Ni-Fe and a high purity Ni
electrode. A preheating treatment at 350 °C and an annealing treatment at 850 °C were carried out to improve
mechanical properties of welded pieces. The pure Ni electrode showed graphite diffusion in the bead with a
uniform distribution of phases, improving weldability and decreasing fragility. Preheating and annealing
treatments increased ductility and improved weldability.Pascual Guillamón, M.; Ferrer Giménez, C.; Rayón Encinas, E. (2009). Weldability of spheroidal graphite ductile cast iron using Ni / Ni-Fe electrodes. Revista de Metalurgia. 45(5):334-338. doi:10.3989/revmetalm.0814S33433845
Long range neutrino forces in the cosmic relic neutrino background
Neutrinos mediate long range forces among macroscopic bodies in vacuum. When
the bodies are placed in the neutrino cosmic background, these forces are
modified. Indeed, at distances long compared to the scale , the relic
neutrinos completely screen off the 2-neutrino exchange force, whereas for
small distances the interaction remains unaffected.Comment: 8 pages, 2 figure
Entropy Rate of Diffusion Processes on Complex Networks
The concept of entropy rate for a dynamical process on a graph is introduced.
We study diffusion processes where the node degrees are used as a local
information by the random walkers. We describe analitically and numerically how
the degree heterogeneity and correlations affect the diffusion entropy rate. In
addition, the entropy rate is used to characterize complex networks from the
real world. Our results point out how to design optimal diffusion processes
that maximize the entropy for a given network structure, providing a new
theoretical tool with applications to social, technological and communication
networks.Comment: 4 pages (APS format), 3 figures, 1 tabl
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