Advanced airway management: a descriptive analysis of complications and factors associated with first-attempt intubation failure in prehospital emergency care

7 p.Objetivos. Analizar las características del manejo de la vía aérea (VA) en emergencias prehospitalarias, sus complicaciones y establecer factores predictores de fracaso en el primer intento de intubación orotraqueal (FIPI). Método. Estudio observacional de cohortes retrospectivo de pacientes que precisaron intubación orotraqueal por el servicio de emergencias prehospitalarias de Castilla La Mancha, desde el 01-06-2017 hasta el 01-01-2021. Se analizaron características de los pacientes, del procedimiento y sus complicaciones, se realizó una regresión logística para detectar factores predictores de FIPI. Resultados. Se incluyeron 425 pacientes, 417 (98,1%) fueron intubados con éxito y 326 (76,7%) en el primer intento. Se registraron 183 complicaciones en 94 pacientes (22,1%). Los factores predictores de FIPI fueron la edad > 55 años (OR = 1,94; IC 95% 1,10-4,23), índice de masa corporal > 30 (OR = 9,14; IC 95% 4,40-19,00); saturación de oxígeno < 90% (OR = 3,33; IC 95% 1,06-10,58); puntuación en la Glasgow Coma Scale entre 9 y 13 (OR = 1,58; IC 95% 1,28-6,9); intubación realizada en vía pública (OR = 2,99; IC 95% 1,42-6,29); posición distinta a la bipedestación (OR = 2,09; IC 95% 1,08-7,25); laringoscopia directa (OR = 2,39; IC 95% 1,20-6,55); uso de estilete (OR = 1,80; IC 95% 1,40-3,78); y clasificación Cormack-Lehane $ 2 (OR = 6,50; IC 95% 3,96-30,68). Conclusiones. El procedimiento de intubación se realizó de forma habitual en el primer intento. Existen factores asociados a FIPI que permiten individualizar el manejo de la VA

An RVE-based multiscale theory of solids with micro-scale inertia and body force effects

A multiscale theory of solids based on the concept of representative volume element (RVE) and accounting for micro-scale inertia and body forces is proposed. A simple extension of the classical Hill–Mandel Principle together with suitable kinematical constraints on the micro-scale displacements provide the variational framework within which the theory is devised. In this context, the micro-scale equilibrium equation and the homogenisation relations among the relevant macro- and micro-scale quantities are rigorously derived by means of straightforward variational arguments. In particular, it is shown that only the fluctuations of micro-scale inertia and body forces about their RVE volume averages may affect the micro-scale equilibrium problem and the resulting homogenised stress. The volume average themselves are mechanically relevant only to the macro-scale

Damage-driven strain localisation in networks of fibres: A computational homogenisation approach

In many applications, such as textiles, fibreglass, paper and several kinds of biological fibrous tissues, the main load-bearing constituents at the micro-scale are arranged as a fibre network. In these materials, rupture is usually driven by micro-mechanical failure mechanisms, and strain localisation due to progressive damage evolution in the fibres is the main cause of macro-scale instability. We propose a strain-driven computational homogenisation formulationbased on Representative Volume Element (RVE), within a framework in which micro-scale fibre damage can lead to macro-scale localisation phenomena. The mechanical stiffness considered here for the fibrous structure system is due to: i) an intra-fibre mechanism in which each fibre is axially stretched, and as a result, it can suffer damage; ii) an inter-fibre mechanism in which the stiffness results from the variation of the relative angle between pairs of fibres. The homogenised tangent tensor, which comes from the contribution of these two mechanisms, is required to detect the so-called bifurcation point at the macro-scale, through the spectral analysis of the acoustic tensor. This analysis can precisely determine the instant at which the macro-scale problem becomes ill-posed. At such a point, the spectral analysis provides information about the macro-scale failure pattern (unit normal and crack-opening vectors). Special attention is devoted to present the theoretical fundamentals rigorously in the light of variational formulations for multi-scale models. Also, the impact of a recent derived more general boundary condition for fibre networks is assessed in the context of materials undergoing softening. Numerical examples showing the suitability of the present methodology are also shown and discussed

Altered Ecology of the Respiratory Tract Microbiome and Nosocomial Pneumonia

10 p.Nosocomial pneumonia is one of the most frequent infections in critical patients. It is primarily associated with mechanical ventilation leading to severe illness, high mortality, and prolonged hospitalization. The risk of mortality has increased over time due to the rise in multidrug-resistant (MDR) bacterial infections, which represent a global public health threat. Respiratory tract microbiome (RTM) research is growing, and recent studies suggest that a healthy RTM positively stimulates the immune system and, like the gut microbiome, can protect against pathogen infection through colonization resistance (CR). Physiological conditions of critical patients and interventions as antibiotics administration and mechanical ventilation dramatically alter the RTM, leading to dysbiosis. The dysbiosis of the RTM of ICU patients favors the colonization by opportunistic and resistant pathogens that can be part of the microbiota or acquired from the hospital environments (biotic or built ones). Despite recent evidence demonstrating the significance of RTM in nosocomial infections, most of the host-RTM interactions remain unknown. In this context, we present our perspective regarding research in RTM altered ecology in the clinical environment, particularly as a risk for acquisition of nosocomial pneumonia. We also reflect on the gaps in the field and suggest future research directions. Moreover, expected microbiome-based interventions together with the tools to study the RTM highlighting the "omics" approaches are discussed.Comunidad de MadridFundación Ramón ArecesInstituto de Salud Carlos IIIFondo Europeo de Desarrollo RegionalCIBERON

The Method of Multiscale Virtual Power for the derivation of a second order mechanical model

A multi-scale model, based on the concept of Representative Volume Element (RVE), is proposed linking a classical continuum at RVE level to a macro-scale strain-gradient theory. The multi-scale model accounts for the effect of body forces and inertia phenomena occurring at the micro-scale. The Method of Multiscale Virtual Power recently proposed by the authors drives the construction of the model. In this context, the coupling between the macro- and micro-scale kinematical descriptors is defined by means of kinematical insertion and homogenisation operators, carefully postulated to ensure kinematical conservation in the scale transition. Micro-scale equilibrium equations as well as formulae for the homogenised (macro-scale) force- and stress-like quantities are naturally derived from the Principle of Multiscale Virtual Power - a variational extension of the Hill-Mandel Principle that enforces the balance of the virtual powers of both scales. As an additional contribution, further insight into the theory is gained with the enforcement of the RVE kinematical constraints by means of Lagrange multipliers. This approach unveils the reactive nature of homogenised force- and stress-like quantities and allows the characterisation of the homogenised stress-like quantities exclusively in terms of RVE boundary data in a straightforward manner.Fil: Blanco, Pablo Javier. Ministério da Ciência, Tecnologia, Inovações e Comunicações. Laboratório Nacional de Computação Científica; BrasilFil: Sánchez, Pablo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: De Souza Neto, Eduardo Alberto. Swansea University; Reino UnidoFil: Feijóo, Raúl Antonino. Ministério da Ciência, Tecnologia, Inovações e Comunicações. Laboratório Nacional de Computação Científica; Brasi

Pulmonary vascular proliferation in patients with severe COVID-19: an autopsy study

3 p.Diffuse alveolar damage and thrombi are the most common lung histopathological lesions reported in patients with severe COVID-19. Although some studies have suggested increased pulmonary angiogenesis, the presence of vascular proliferation in COVID-19 lungs has not been well characterised. Glomeruloid-like microscopic foci and/or coalescent vascular proliferations measuring up to 2 cm were present in the lung of 14 out of 16 autopsied patients. These lesions expressed CD31, CD34 and vascular endothelial cadherin. Platelet-derived growth factor receptor-? immunohistochemistry and dual immunostaining for CD34/smooth muscle actin demonstrated the presence of pericytes. These vascular alterations may contribute to the severe and refractory hypoxaemia that is common in patients with severe COVID-19.Instituto de Salud Carlos IIICIBERONCInstituto Ramón y Cajal de Investigación Sanitaria Intramural COVID1

Simplified model of battery energy-stored quasi-Z-source inverter-based photovoltaic power plant with Twofold energy management system

The use of a battery energy-stored quasi-Z-source inverter (BES-qZSI) for large-scale PV power plants exhibits promising features due to the combination of qZSI and battery as energy storage system, such as single-stage power conversion (without additional DC/DC boost converter), improvements in the output waveform quality (due to the elimination of switching dead time), and continuous and smooth delivery of energy to the grid (through the battery energy storage system). This paper presents a new simplified model of a BES-qZSI to represent the converter dynamics with sufficient accuracy while using a less complex model than the detailed model (including the modelling of all switches and switching pulses). It is based on averaged values of the variables, voltage/current sources, and the same control circuit than the detailed model, except for the switching pulses generation. The simplified model enables faster time-domain simulation and is useful for control design and dynamic analysis purposes. Additionally, an energy management system has been developed to govern the power supply to grid under two possible scenarios: 1) System operator command following; or 2) economic dispatch of the stored energy. The results obtained from simulations and experimental hardware-in-the-loop (HIL) setup for different operating conditions of the grid-connected large-scale PV power plant with battery energy storage under study demonstrate the validity of the proposed simplified model to represent the dynamics of the converter and PV power plant for steady-state stability studies, long-term simulations, or large electric power systems. © 2021 The AuthorsThis work was partially supported by the Spain's Ministerio de Ciencia, Innovaci?n y Universidades (MCIU), Agencia Estatal de Investigaci?n (AEI), and Fondo Europeo de Desarrollo Regional (FEDER) Uni?n Europea (UE) (grant number RTI2018-095720-B-C32), by the Federal Center for Technological Education of Minas Gerais, Brazil (process number 23062?010087/2017-51) and by the National Council of Technological and Scientific Development (CNPq-Brazil

Electrochemical and mechanical behavior in polycrystalline CoNi-Ga shape memory alloys

"Electrochemical behavior and microstructure was studied in polycrystalline Co38.3Ni32.1Ga29.6 alloy using the electrochemical technique of polarization curves in a medium of 3.5 wt % NaCl and 0.5M H2SO4. The importance of these alloys is due to their functional behavior, as shape memory alloys with ferromagnetic properties. The alloy was fabricated by induction furnace and the characterizations were performed using differential scanning calorimetry (DSC), nanoindenter tests and X-ray diffraction (XRD) The analysis of the kinetics of corrosion was conducted using cyclic sweep voltammetry curves with potentiostat/galvanostat. The corrosion morphologies were also analyzed by scanning electron microscopy (SEM). The kinetics of corrosion was found to be highest in the acid media and the alloy with thermal treatment in 3.5 wt% NaCl (A-TT-NaCl) shows a icorr lower that the alloy without thermal treatment (A-NaCl) in the same solution. On polarization curves, the current alloys exhibited a general dissolution in the anodic branch until certain potential was reached where a spontaneous passive zone occurred in 3.5 wt% NaCl media, similar behavior was found in acid media where, under high potentials occurs a repassivation zone at 427mV and elements such as Co and Ni were present in a higher percentage for all the corrosion deposits.

High-Flow Oxygen with Capping or Suctioning for Tracheostomy Decannulation

9 p.BACKGROUND When patients with a tracheostomy tube reach a stage in their care at which decannulation appears to be possible, it is common practice to cap the tracheostomy tube for 24 hours to see whether they can breathe on their own. Whether this approach to establishing patient readiness for decannulation leads to better outcomes than one based on the frequency of airway suctioning is unclear. METHODS In five intensive care units (ICUs), we enrolled conscious, critically ill adults who had a tracheostomy tube; patients were eligible after weaning from mechanical ventilation. In this unblinded trial, patients were randomly assigned either to undergo a 24-hour capping trial plus intermittent high-flow oxygen therapy (control group) or to receive continuous high-flow oxygen therapy with frequency of suctioning being the indicator of readiness for decannulation (intervention group). The primary outcome was the time to decannulation, compared by means of the log-rank test. Secondary outcomes included decannulation failure, weaning failure, respiratory infections, sepsis, multiorgan failure, durations of stay in the ICU and hospital, and deaths in the ICU and hospital. RESULTS The trial included 330 patients; the mean (±SD) age of the patients was 58.3±15.1 years, and 68.2% of the patients were men. A total of 161 patients were assigned to the control group and 169 to the intervention group. The time to decannulation was shorter in the intervention group than in the control group (median, 6 days [interquartile range, 5 to 7] vs. 13 days [interquartile range, 11 to 14]; absolute difference, 7 days [95% confidence interval, 5 to 9]). The incidence of pneumonia and tracheobronchitis was lower, and the duration of stay in the hospital shorter, in the intervention group than in the control group. Other secondary outcomes were similar in the two groups. CONCLUSIONS Basing the decision to decannulate on suctioning frequency plus continuous highflow oxygen therapy rather than on 24-hour capping trials plus intermittent highflow oxygen therapy reduced the time to decannulation, with no evidence of a between-group difference in the incidence of decannulation failure. (REDECAP ClinicalTrials.gov number, NCT02512744.