A efetividade do decúbito ventral na Acute Respiratory Distress Syndrome: revisão sistemática

Background: prone Position is a well-established evidence-based clinical practice in patients with Acute Respiratory Distress Syndrome undergoing invasive mechanical ventilation. Little evidence in non-intubated patients is known. Due to the increasing rate of acute respiratory distress syndrome, the need to know the effectiveness in non-intubated patients has emerged. Objective: to know the effectiveness of prone position in the treatment of acute respiratory distress syndrome in non-intubated adults. Methodology: Systematic reviews based on the manual of Joanna Briggs Institute and carried out using PICO strategy. Research conducted in August 2021 in the access platforms Web of Science, PubMed, and EBSCO Host. Selection was done after elimination of duplicates, title reading, reading of abstracts, and full texts according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses diagram Results: 741 results were identified, and seven were included in the review. Conclusion: Early prone position is advantageous in non-intubated patients with mild and moderate acute respiratory distress syndrome. A risk intervention in non-intubated patients with Severe Acute Respiratory Distress Syndrome. Mortality/survival, physiological/clinical, adverse events/effects and functioning outcomes were identified as predictors of success/failure of prone position.Marco contextual: posición prona es una práctica clínica, basada en evidencia, conocida en pacientes con Síndrome de Dificultad Respiratoria Aguda con ventilación mecánica invasiva. Hay poca evidencia en pacientes no entubados. La creciente tasa de síndrome de distrés respiratorio agudo originó la necesidad de desarrollar esfuerzos para conocer su efectividad en pacientes no intubados. Objetivo: conocer la efectividad del decúbito prono en el tratamiento del síndrome de distrés respiratorio agudo en adultos no intubados. Metodología: revisión sistemática basadas en el manual del Instituto Joanna Briggs y mediante la estrategia PICO. La búsqueda ocurrió en agosto 2021 en las plataformas de acceso Web of Science, PubMed y EBSCO Host. Selección realizada por previa eliminación de duplicados, lectura de títulos, resúmenes y textos completos de acuerdo con el diagrama Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Resultados: se identificaron 741 resultados, siete incluyeron la revisión. Conclusión: la posición prona temprana demostró ser ventajosa en pacientes no intubados con Síndrome de Dificultad Respiratoria Aguda leve y moderado. Intervención riesgosa en pacientes no intubados con Síndrome de Dificultad Respiratoria Aguda grave. Indicadores de mortalidad/supervivencia, fisiológicos/clínicos, de eventos/efectos adversos e indicadores funcionales, fueron identificados como predictores de éxito/fracaso de la posición prono.Enquadramento: o decúbito ventral é uma prática clínica baseada na evidência que se encontra bem estabelecida em pacientes com Acute Respiratory Distress Syndrome submetidos a ventilação mecânica invasiva. Porém, existe parca evidência em pacientes não intubados. Face ao aumento da taxa de Acute Respiratory Distress Syndrome, emergiu a necessidade de conhecer a sua eficácia em pacientes não intubados. Objetivo: conhecer a efetividade do decúbito ventral no tratamento da Acute Respiratory Distress Syndrome em adultos não intubados. Metodologia: revisão sistemática fundamentada no manual de Joanna Briggs Institute, com recurso à estratégia PICO. Pesquisa realizada em agosto de 2021, nas plataformas de acesso Web of Science, PubMed e EBSCO Host. Seleção realizada após eliminação de duplicados, leitura do título, de resumos e textos integrais de acordo com o diagrama Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Resultados: identificaram-se 741 resultados, sendo sete os incluídos na revisão. Conclusão: O decúbito ventral precoce revelou-se vantajoso em pacientes não intubados com Acute Respiratory Distress Syndrome ligeira e moderada. É uma intervenção de risco em pacientes não intubados com Acute Respiratory Distress Syndrome grave. Foram identificados indicadores de mortalidade/ sobrevida, fisiológicos/ clínicos, de eventos/ efeitos adversos e indicadores funcionais como preditores de sucesso/ insucesso do decúbito ventral

Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory

In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (Xmax) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with Xmax distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energy-dependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data

Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory

The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gamma rays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations

The dynamic range of the upgraded surface-detector stations of AugerPrime

The detection of ultra-high-energy cosmic rays by means of giant detector arrays is often limited by the saturation of the recorded signals near the impact point of the shower core at the ground, where the particle density dramatically increases. The saturation affects in particular the highest energy events, worsening the systematic uncertainties in the reconstruction of the shower characteristics. The upgrade of the Pierre Auger Observatory, called AugerPrime, includes the installation of an 1-inch Small PhotoMultiplier Tube (SPMT) inside each water-Cherenkov station (WCD) of the surface detector array. The SPMT allows an unambiguous measurement of signals down to about 250m from the shower core, thus reducing the number of events featuring a saturated station to a negligible level. In addition, a 3.8m2 plastic scintillator (Scintillator Surface Detector, SSD) is installed on top of each WCD. The SSD is designed to match the WCD (with SPMT) dynamic range, providing a complementary measurement of the shower components up to the highest energies. In this work, the design and performances of the upgraded AugerPrime surface-detector stations in the extended dynamic range are described, highlighting the accuracy of the measurements. A first analysis employing the unsaturated signals in the event reconstruction is also presented

Investigating multiple elves and halos above strong lightning with the fluorescence detectors of the Pierre Auger Observatory

ELVES are being studied since 2013 with the twenty-four FD Telescopes of the Pierre Auger Observatory, in the province of Mendoza (Argentina), the world’s largest facility for the study of ultra-high energy cosmic rays. This study exploits a dedicated trigger and extended readout. Since December 2020, this trigger has been extended to the three High levation Auger Telescopes (HEAT), which observe the night sky at elevation angles between 30 and 60 degrees, allowing a study of ELVES from closer lightning. The high time resolution of the Auger telescopes allows us to upgrade reconstruction algorithms and to do detailed studies on multiple ELVES. The origin of multiple elves can be studied by analyzing the time difference and the amplitude ratio between flashes and comparing them with the properties of radio signals detected by the ENTLN lightning network since 2018. A fraction of multi-ELVES can also be interpreted as halos following ELVES. Halos are disc-shaped light transients emitted at 70-80 km altitudes, appearing at the center of the ELVES rings, due to the rearrangement of electric charges at the base of the ionosphere after a strong lightning event