Dimensional hyper-reduction of nonlinear finite element models via empirical cubature

We present a general framework for the dimensional reduction, in terms of number of degrees of freedom as well as number of integration points (“hyper-reduction”), of nonlinear parameterized finite element (FE) models. The reduction process is divided into two sequential stages. The first stage consists in a common Galerkin projection onto a reduced-order space, as well as in the condensation of boundary conditions and external forces. For the second stage (reduction in number of integration points), we present a novel cubature scheme that efficiently determines optimal points and associated positive weights so that the error in integrating reduced internal forces is minimized. The distinguishing features of the proposed method are: (1) The minimization problem is posed in terms of orthogonal basis vector (obtained via a partitioned Singular Value Decomposition) rather that in terms of snapshots of the integrand. (2) The volume of the domain is exactly integrated. (3) The selection algorithm need not solve in all iterations a nonnegative least-squares problem to force the positiveness of the weights. Furthermore, we show that the proposed method converges to the absolute minimum (zero integration error) when the number of selected points is equal to the number of internal force modes included in the objective function. We illustrate this model reduction methodology by two nonlinear, structural examples (quasi-static bending and resonant vibration of elastoplastic composite plates). In both examples, the number of integration points is reduced three order of magnitudes (with respect to FE analyses) without significantly sacrificing accuracy.Peer ReviewedPostprint (published version

Modelación numérica con elementos finitos del concreto reforzado con fibras cortas mediante un modelo constitutivo de Daño – Plasticidad

Esta tesis de maestría tiene como objetivo analizar, desarrollar, implementar y validar un modelo constitutivo que represente el comportamiento de estructuras de concreto reforzado con fibras cortas por medio del método de los elementos finitos. El modelo implementado considera un estado plano de esfuerzos, deformaciones infinitesimales y cargas aplicadas estáticas. Inicialmente se simuló el comportamiento estructural en el rango elástico por medio de un modelo de material compuesto basado en la teoría de mezclas clásica. Este modelo fue implementado en el método de los elementos finitos considerando una inclinación de las fibras aleatoria y diferente en cada elemento finito. Del análisis estadístico realizado se obtuvieron las propiedades mecánicas promedio del concreto reforzado con fibras cortas y se concluyó que tal material exhibe un comportamiento isótropo. Para describir el comportamiento inelástico del material se utilizaron varios modelos constitutivos y se analizaron sus ventajas y desventajas. Finalmente se desarrolló un nuevo modelo constitutivo de plasticidad que permite tener resistencias a tracción y a compresión diferentes. El modelo constitutivo propuesto se basa en la formulación de la teoría de la plasticidad y en el dominio elástico definido por el modelo de daño continuo de Oliver y colaboradores (1990). Algunos ensayos experimentales de probetas sometidas a fuerza axial o flexión se simularon con este modelo mostrando resultados satisfactorios. / Abstract. The objectives of this thesis are: to analyze, develop, implement and validate a constitutive model which represents the structural behavior of the short fiber reinforced concrete by means of finite element methods. The implemented model considers plane stress state, infinitesimal strain and applied static loads. Initially, the structural behavior in elastic regime is modeling by means of a composite material model based on classic mixing theory. This model was implemented in the finite element methods considering a random and different fiber orientation each finite element. In the statistical analysis, the average mechanical properties of the short fiber reinforced concrete were obtained and the conclusion is that the material exhibits an isotropic behavior. In order to describe the inelastic behavior of the material, some constitutive models were used and its advantage and drawback were analyzed. Finally, a new plasticity constitutive model with difference between the tensile and compressive strength was developed. The proposed constitutive model is based on the formulation of plasticity theory and in the elastic domain defined by the continuum damage model of Oliver and collaborators (1990). Some experimental test of specimens subjected to axial forces or bending were simulated with this model and its results were satisfactory.Maestrí

High performance reduced order modeling techniques based on optimal energy quadrature: application to geometrically non-linear multiscale inelastic material modeling

A High-Performance Reduced-Order Model (HPROM) technique, previously presented by the authors in the context of hierarchical multiscale models for non linear-materials undergoing infinitesimal strains, is generalized to deal with large deformation elasto-plastic problems. The proposed HPROM technique uses a Proper Orthogonal Decomposition procedure to build a reduced basis of the primary kinematical variable of the micro-scale problem, defined in terms of the micro-deformation gradient fluctuations. Then a Galerkin-projection, onto this reduced basis, is utilized to reduce the dimensionality of the micro-force balance equation, the stress homogenization equation and the effective macro-constitutive tangent tensor equation. Finally, a reduced goal-oriented quadrature rule is introduced to compute the non-affine terms of these equations. Main importance in this paper is given to the numerical assessment of the developed HPROM technique. The numerical experiments are performed on a micro-cell simulating a randomly distributed set of elastic inclusions embedded into an elasto-plastic matrix. This micro-structure is representative of a typical ductile metallic alloy. The HPROM technique applied to this type of problem displays high computational speed-ups, increasing with the complexity of the finite element model. From these results, we conclude that the proposed HPROM technique is an effective computational tool for modeling, with very large speed-ups and acceptable accuracy levels with respect to the high-fidelity case, the multiscale behavior of heterogeneous materials subjected to large deformations involving two well-separated scales of length.Peer ReviewedPostprint (author's final draft

Model Order Reduction in computational multiscale fracture mechanics

Nowadays, the model order reduction techniques have become an intensive research eld because of the increasing interest in the computational modeling of complex phenomena in multi-physic problems, and its conse- quent increment in high-computing demanding processes; it is well known that the availability of high-performance computing capacity is, in most of cases limited, therefore, the model order reduction becomes a novelty tool to overcome this paradigm, that represents an immediately challenge in our research community. In computational multiscale modeling for instance, in order to study the interaction between components, a di erent numerical model has to be solved in each scale, this feature increases radically the computational cost. We present a reduced model based on a multi-scale framework for numerical modeling of the structural failure of heterogeneous quasi-brittle materials using the Strong Discontinuity Approach (CSD). The model is assessed by application to cementitious materials. The Proper Orthogonal Decomposition (POD) and the Reduced Order Integration Cubature are the pro- posed techniques to develop the reduced model, these two techniques work together to reduce both, the complexity and computational time of the high-delity model, in our case the FE2 standard modelPeer ReviewedPostprint (author's final draft

Reduced order modeling strategies for computational multiscale fracture

The paper proposes some new computational strategies for affordably solving multiscale fracture problems through a FE2 approach. To take into account the mechanical effects induced by fracture at the microstructure level the Representative Volume Element (RVE), assumed constituted by an elastic matrix and inclusions, is endowed with a large set of cohesive softening bands providing a good representation of the possible microstructure crack paths. The RVE response is then homogenized in accordance with a model previously developed by the authors and upscaled to the macro-scale level as a continuum stress–strain constitutive equation, which is then used in a conventional framework of a finite element modeling of propagating fracture. For reduced order modeling (ROM) purposes, the RVE boundary value problem is first formulated in displacement fluctuations and used, via the Proper Orthogonal Decomposition (POD), to find a low-dimension space for solving the reduced problem. A domain separation strategy is proposed as a first technique for model order reduction: unconventionally, the low-dimension space is spanned by a basis in terms of fluctuating strains, as primitive kinematic variables, instead of the conventional formulation in terms of displacement fluctuations. The RVE spatial domain is then decomposed into a regular domain (made of the matrix and the inclusions) and a singular domain (constituted by cohesive bands), the required RVE boundary conditions are rephrased in terms of strains and imposed via Lagrange multipliers in the corresponding variational problem. Specific low-dimensional strain basis is then derived, independently for each domain, via the POD of the corresponding strain snapshots. Next step consists of developing a hyper-reduced model (HPROM). It is based on a second proposed technique, the Reduced Optimal Quadrature (ROQ) which, again unconventionally, is determined through optimization of the numerical integration of the primitive saddle-point problem arising from the RVE problem, rather than its derived variational equations, and substitutes the conventional Gauss quadrature. The ROQ utilizes a very reduced number of, optimally placed, sampling points, the corresponding weights and placements being evaluated through a greedy algorithm. The resulting low-dimensional and reduced-quadrature variational problem translates into very relevant savings on the computational cost and high computational speed-ups. Particular attention is additionally given to numerical tests and performance evaluations of the new hyper-reduced methodology, by “a-priori” and “a-posteriori” error assessments. Moreover, for the purposes of validation of the present techniques, a real structural problem exhibiting propagating fracture at two-scales is modeled on the basis of the strain injection-based multiscale approach previously developed by the authors. The performance of the proposed strategy, in terms of speed-up vs. error, is deeply analyzed and reported.Peer ReviewedPostprint (published version

A multi-criteria h-adaptive finite-element framework for industrial part-scale thermal analysis in additive manufacturing processes

This work presents an h-adaptive finite-element (FE) strategy to address the numerical simulation of additive manufacturing (AM) of large-scale parts. The wire-arc additive manufacturing is chosen as the demonstrative technology for its manufacturing capabilities suitable for industrial purposes. The scanning path and processing parameters of the simulation are provided via a RS-274 (GCode) file, being the same as the one delivered to the AM machine. The approach is suitable for industrial applications and can be applied to other AM processes. To identify the location in the FE mesh of the heat affected zone (HAZ), a collision detection algorithm based on the separating axis theorem is used. The mesh is continuously adapted to guarantee the necessary mesh resolution to capture the phenomena inside and outside the HAZ. To do so, a multi-criteria adaptive mesh refinement and coarsening (AMR) strategy is used. The AMR includes a geometrical criterion to guarantee the FE size within the HAZ, and a Zienkiewicz–Zhu-based a-posteriori error estimator to guarantee the solution accuracy elsewhere. Thus, the number of active FEs is controlled and mesh manipulation by the end-user is avoided. Numerical simulations comparing the h-adaptive strategy with the (reference) fixed fine meshes are performed to prove the computational cost efficiency and the solution accuracy.The financial support from the Spanish Ministry of Economy and Competitiveness, through the Severo Ochoa Programme for Centres of Excellence in R&D (CEX2018-000797-S), is gratefully acknowledged. This work has been supported by the European Union’s horizon 2020 research and innovation programme (H2020-DT-2019-1 no. 872570) under the KYKLOS 4.0 Project (An Advanced Circular and Agile Manufacturing Ecosystem based on rapid reconfigurable manufacturing process and individualized consumer preferences) and by the Ministry of Science, Innovation and Universities (MCIU) via: the PriMuS project (Printing pattern based and MultiScale enhanced performance analysis of advanced Additive Manufacturing components, ref. num. PID2020-115575RB-I00). J. Baiges gratefully acknowledges the support of the Spanish Government through the Ramón y Cajal Grant RYC-2015-17367. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.Peer ReviewedPostprint (published version

Colombian consensus on the treatment of Placenta Accreta Spectrum (PAS)

Introducción: el espectro de acretismo placentario (EAP) es una condición asociada a sangrado masivo posparto y mortalidad materna. Las guías de manejo publicadas en países de altos ingresos recomiendan la participación de grupos interdisciplinarios en hospitales con recursos suficientes para realizar procedimientos complejos. Sin embargo, algunas de las recomendaciones de estas guías resultan difíciles de aplicar en países de bajos y medianos ingresos. Objetivos: este consenso busca formular recomendaciones generales para el tratamiento del EAP en Colombia. Materiales y métodos: en el consenso participaron 23 panelistas, quienes respondieron 31 preguntas sobre el tratamiento de EAP. Los panelistas fueron seleccionados con base en la participación en dos encuestas realizadas para determinar la capacidad resolutiva de hospitales en el país y la región. Se utilizó la metodología Delphi modificada, incorporando dos rondas sucesivas de discusión. Para emitir las recomendaciones el grupo tomó en cuenta la opinión de los participantes, que lograron un consenso mayor al 80 %, así como las barreras y los facilitadores para su implementación. Resultados: el consenso formuló cinco recomendaciones integrando las respuestas de los panelistas. Recomendación 1. Las instituciones de atención primaria deben realizar búsqueda activa de EAP en pacientes con factores de riesgo: placenta previa e historia de miomectomía o cesárea en embarazo previo. En caso de haber signos sugestivos de EAP por ecografía, las pacientes deben ser remitidas de manera inmediata, sin tener una edad gestacional mínima, a hospitales reconocidos como centros de referencia. Las modalidades virtuales de comunicación y atención en salud pueden facilitar la interacción entre las instituciones de atención primaria y los centros de referencia para EAP. Se debe evaluar el beneficio y riesgo de las modalidades de telemedicina. Recomendación 2. Es necesario que se definan hospitales de referencia para EAP en cada región de Colombia, asegurando el cubrimiento de la totalidad del territorio nacional. Es aconsejable concentrar el flujo de pacientes afectadas por esta condición en unos pocos hospitales, donde haya equipos de cirujanos con entrenamiento específico en EAP, disponibilidad de recursos especializados y un esfuerzo institucional por mejorar la calidad de atención, en busca de tener mejores resultados en la salud de las gestantes con esta condición. Para lograr ese objetivo los participantes recomiendan que los entes reguladores de la prestación de servicios de salud a nivel nacional, regional o local vigilen el proceso de remisión de estas pacientes, facilitando rutas administrativas en caso de que no exista contrato previo entre el asegurador y el hospital o la clínica seleccionada (IPS). Recomendación 3. En los centros de referencia para pacientes con EAP se invita a la creación de equipos que incorporen un grupo fijo de especialistas (obstetras, urólogos, cirujanos generales, radiólogos intervencionistas) encargados de atender todos los casos de EAP. Es recomendable que esos grupos interdisciplinarios utilicen el modelo de “paquete de intervención” como guía para la preparación de los centros de referencia para EAP. Este modelo consta de las siguientes actividades: preparación de los servicios, prevención e identificación de la enfermedad, respuesta ante la presentación de la enfermedad, aprendizaje luego de cada evento. La telemedicina facilita el tratamiento de EAP y debe ser tenida en cuenta por los grupos interdisciplinarios que atienden esta enfermedad. Recomendación 4. Los residentes de Obstetricia deben recibir instrucción en maniobras útiles para la prevención y el tratamiento del sangrado intraoperatorio masivo por placenta previa y EAP, tales como: la compresión manual de la aorta, el torniquete uterino, el empaquetamiento pélvico, el bypass retrovesical y la maniobra de Ward. Los conceptos básicos de diagnóstico y tratamiento de EAP deben incluirse en los programas de especialización en Ginecología y Obstetricia en Colombia. En los centros de referencia del EAP se deben ofrecer programas de entrenamiento a los profesionales interesados en mejorar sus competencias en EAP de manera presencial y virtual. Además, deben ofrecer soporte asistencial remoto (telemedicina) permanente a los demás hospitales en su región, en relación con pacientes con esa enfermedad. Recomendación 5. La finalización de la gestación en pacientes con sospecha de EAP y placenta previa, por imágenes diagnósticas, sin evidencia de sangrado vaginal activo, debe llevarse a cabo entre las semanas 34 y 36 6/7. El tratamiento quirúrgico debe incluir intervenciones secuenciales que pueden variar según las características de la lesión, la situación clínica de la paciente y los recursos disponibles. Las opciones quirúrgicas (histerectomía total y subtotal, manejo quirúrgico conservador en un paso y manejo expectante) deben incluirse en un protocolo conocido por todo el equipo interdisciplinario. En escenarios sin diagnóstico anteparto, es decir, ante un hallazgo intraoperatorio de EAP (evidencia de abultamiento violáceo o neovascularización de la cara anterior del útero), y con participación de personal no entrenado, se plantean tres situaciones: Primera opción: en ausencia de indicación de nacimiento inmediato o sangrado vaginal, se recomienda diferir la cesárea (cerrar la laparotomía antes de incidir el útero) hasta asegurar la disponibilidad de los recursos recomendados para llevar a cabo una cirugía segura. Segunda opción: ante indicación de nacimiento inmediato (por ejemplo, estado fetal no tranquilizador), pero sin sangrado vaginal o indicación de manejo inmediato de EAP, se sugiere realizar manejo en dos tiempos: se realiza la cesárea evitando incidir la placenta, seguida de histerorrafia y cierre de abdomen, hasta asegurar la disponibilidad de los recursos recomendados para llevar a cabo una cirugía segura. Tercera opción: en presencia de sangrado vaginal que hace imposible diferir el manejo definitivo de EAP, es necesario extraer el feto por el fondo del útero, realizar la histerorrafia y reevaluar. En ocasiones, el nacimiento del feto disminuye el flujo placentario y el sangrado vaginal se reduce o desaparece, lo que hace posible diferir el manejo definitivo de EAP. Si el sangrado significativo persiste, es necesario continuar con la histerectomía haciendo uso de los recursos disponibles: compresión manual de la aorta, llamado inmediato a los cirujanos con mejor entrenamiento disponible, soporte de grupos expertos de otros hospitales a través de telemedicina. Si una paciente con factores de riesgo para EAP (por ejemplo, miomectomía o cesárea previa) presenta retención de placenta posterior al parto vaginal, es recomendable confirmar la posibilidad de dicho diagnóstico (por ejemplo, realizando una ecografía) antes de intentar la extracción manual de la placenta. Conclusiones: esperamos que este primer consenso colombiano de EAP sirva como base para discusiones adicionales y trabajos colaborativos que mejoren los resultados clínicos de las mujeres afectadas por esta enfermedad. Evaluar la aplicabilidad y efectividad de las recomendaciones emitidas requerirá investigaciones adicionales.Q4Pacientes con Espectro de Acretismo Placentario (EAP)Introduction: Placenta accreta spectrum (PAS) is a condition associated with massive postpartum bleeding and maternal mortality. Management guidelines published in high income countries recommend the participation of interdisciplinary teams in hospitals with sufficient resources for performing complex procedures. However, some of the recommendations contained in those guidelines are difficult to implement in low and medium income countries. Objectives: The aim of this consensus is to draft general recommendations for the treatment of PAS in Colombia. Materials and Methods: Twenty-three panelists took part in the consensus with their answers to 31 questions related to the treatment of PAS. The panelists were selected based on participation in two surveys designed to determine the resolution capabilities of national and regional hospitals. The modified Delphi methodology was used, introducing two successive discussion rounds. The opinions of the participants, with a consensus of more than 80 %, as well as implementation barriers and facilitators, were taken into consideration in order to issue the recommendations. Results: The consensus drafted five recommendations, integrating the answers of the panelists. Recommendation 1. Primary care institutions must undertake active search of PAS in patients with risk factors: placenta praevia and history of myomectomy or previous cesarean section. In case of ultrasound signs suggesting PAS, patients must be immediately referred, without a minimum gestational age, to hospitals recognized as referral centers. Online communication and care modalities may facilitate the interaction between primary care institutions and referral centers for PAS. The risks and benefits of telemedicine modalities must be weighed. Recommendation 2. Referral hospitals for PAS need to be defined in each region of Colombia, ensuring coverage throughout the national territory. It is advisable to concentrate the flow of patients affected by this condition in a few hospitals with surgical teams specifically trained in PAS, availability of specialized resources, and institutional efforts at improving quality of care with the aim of achieving better health outcomes in pregnant women with this condition. To achieve this goal, participants recommend that healthcare regulatory agencies at a national and regional level should oversee the process of referral for these patients, expediting administrative pathways in those cases in which there is no prior agreement between the insurer and the selected hospital or clinic.Recommendation 3. Referral centers for patients with PAS are urged to build teams consisting of a fixed group of specialists (obstetricians, urologists, general surgeons, interventional radiologists) entrusted with the care of all PAS cases. It is advisable for these interdisciplinary teams to use the “intervention bundle” model as a guidance for building PAS referral centers. This model comprises the following activities: service preparedness, disease prevention and identification, response to the occurrence of the disease, and debriefing after every event. Telemedicine facilitates PAS treatment and should be taken into consideration by interdisciplinary teams caring for this disease. Recommendation 4. Obstetrics residents must be instructed in the performance of maneuvers that are useful for the prevention and treatment of massive intraoperative bleeding due to placenta praevia and PAS, including manual aortic compression, uterine tourniquet, pelvic packing, retrovesical bypass, and Ward maneuver. Specialization Obstetrics and Gynecology programs in Colombia must include the basic concepts of the diagnosis and treatment of PAS. Referral centers for PAS must offer online and in-person training programs for professionals interested in improving their competencies in PAS. Moreover, they must offer permanent remote support (telemedicine) to other hospitals in their region for patients with this condition. Recommendation 5. Patients suspected of having PAS and placenta praevia based on imaging, with no evidence of active vaginal bleeding, must be delivered between weeks 34 and 36 6/7. Surgical treatment must include sequential interventions that may vary depending on the characteristics of the lesion, the clinical condition of the patient and the availability of resources. The surgical options (total and subtotal hysterectomy, one-stage conservative surgical management and watchful waiting) must be included in a protocol known by the entire interdisciplinary team. In situations in which an antepartum diagnosis is lacking, that is to say, in the face of intraoperative finding of PAS (evidence of purple bulging or neovascularization of the anterior aspect of the uterus), and the participation of untrained personnel, three options are considered: Option 1: In the absence of indication of immediate delivery or of vaginal delivery, the recommendation is to postpone the cesarean section (close the laparotomy before incising the uterus) until the recommended resources for safe surgery are secured. Option 2: If there is an indication for immediate delivery (e.g., non-reassuring fetal status) but there is absence of vaginal bleeding or indication for immediate PAS management, a two-stage management is suggested: cesarean section avoiding placental incision, followed by uterine repair and abdominal closure, until the availability of the recommended resources for safe surgery is ascertained. Option 3: In the event of vaginal bleeding that prevents definitive PAS management, the fetus must be delivered through the uterine fundus, followed by uterine repair and reassessment of the situation. Sometimes, fetal delivery diminishes placental flow and vaginal bleeding is reduced or disappears, enabling the possibility to postpone definitive management of PAS. In case of persistent significant bleeding, hysterectomy should be performed, using all available resources: manual aortic compression, immediate call to the surgeons with the best available training, telemedicine support from expert teams in other hospitals.If a patient with risk factors for PAS (e.g., myomectomy or previous cesarean section) has a retained placenta after vaginal delivery, it is advisable to confirm the possibility of such diagnosis (by means of ultrasound, for example) before proceeding to manual extraction of the placenta.Conclusions: It is our hope that this first Colombian consensus on PAS will serve as a basis for additional discussions and collaborations that can result in improved clinical outcomes for women affected by this condition. Additional research will be required in order to evaluate the applicability and effectiveness of these recommendations.https://orcid.org/0000-0001-6822-0374Revista Nacional - IndexadaCN

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

XVI International Congress of Control Electronics and Telecommunications: "Techno-scientific considerations for a post-pandemic world intensive in knowledge, innovation and sustainable local development"

Este título, sugestivo por los impactos durante la situación de la Covid 19 en el mundo, y que en Colombia lastimosamente han sido muy críticos, permiten asumir la obligada superación de tensiones sociales, políticas, y económicas; pero sobre todo científicas y tecnológicas. Inicialmente, esto supone la existencia de una capacidad de la sociedad colombiana por recuperar su estado inicial después de que haya cesado la perturbación a la que fue sometida por la catastrófica pandemia, y superar ese anterior estado de cosas ya que se encontraban -y aún se encuentran- muchos problemas locales mal resueltos, medianamente resueltos, y muchos sin resolver: es decir, habrá que rediseñar y fortalecer una probada resiliencia social existente - producto del prolongado conflicto social colombiano superado parcialmente por un proceso de paz exitoso - desde la tecnociencia local; como lo indicaba Markus Brunnermeier - economista alemán y catedrático de economía de la Universidad de Princeton- en su libro The Resilient Society…La cuestión no es preveerlo todo sino poder reaccionar…aprender a recuperarse rápido.This title, suggestive of the impacts during the Covid 19 situation in the world, and which have unfortunately been very critical in Colombia, allows us to assume the obligatory overcoming of social, political, and economic tensions; but above all scientific and technological. Initially, this supposes the existence of a capacity of Colombian society to recover its initial state after the disturbance to which it was subjected by the catastrophic pandemic has ceased, and to overcome that previous state of affairs since it was found -and still is find - many local problems poorly resolved, moderately resolved, and many unresolved: that is, an existing social resilience test will have to be redesigned and strengthened - product of the prolonged Colombian social conflict partially overcome by a successful peace process - from local technoscience; As Markus Brunnermeier - German economist and professor of economics at Princeton University - indicates in his book The Resilient Society...The question is not to foresee everything but to be able to react...learn to recover quickly.Bogot

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat