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Background: The first case of COVID-19 was reported in Chile on March 3, 2020. Public and private hospitals were managed in a centralized manner. On May 30, Chile had 99,668 cases, 1054 deaths, 1383 ICU patients, 1174 patients on invasive mechanical ventilation (IMV), and 51 patients on non-invasive ventilation (NIMV). Research question: What are the variables associated with condition at discharge?Method: We performed a retrospective cohort study of 529 patients with a positive RT-PCR for SARS CoV-2who were consecutively discharged between March 14 and June 4, 2020, at Clínica Dávila, Santiago. Patients were analyzed according to laboratory variables on admission, Quality-Adjusted Life Year (QALY) score, health insurance, and type of respiratory support. Condition at discharge was survivor, non-survivor, or transfer to another center. Differences were evaluated by Chi-square test, Student’s t test, or Mann–Whitney U test. Logistic regression analysis was performed to identify variables that were predictive of condition at discharge.Results: Median (interquartile range, IQR) age was 49 (37–62) years, and the median (IQR) stay in the hospital was 6 (3–10) days. A total of 352 patients (66.5%) had respiratory symptoms, 177 (33.4%) had other symptoms or diagnoses on admission, and 116 required ventilatory support; 448 (84.7%) were survivors, 54 (10.2%) were non-survivors, and 27 (5.1%) were transferred. The median ages of the survivors and non-survivors were 46 (36–59) and 75.5 (66–84), respectively.Having state health insurance increased the risk of death by 2.8-fold (OR, 2.825; 95% CI: 1.383–5.772; P = 0.004). Multivariate analysis revealed the following predictive variables: age ≥ 60 years (OR, 15.3; 95% CI: 7.25–32.2; P = .001); PaO2/FiO2 on admission ≤ 200 vs > 200 (OR, 5,205; CI 95%: 1,942–13,94); high-sensitivity troponin, ≥ 15 vs 15 points (OR, 14,011; 95% CI: 4,826–40,679; P=.001).Interpretation: The variables analyzed and patient’s clinical evolution may allow assignment of ICU beds to patients with the greatest chance of survival, especially in countries or regions where this resource is limited.

Compared to conventional concrete, high-performance concrete production offers such benefits as greater ease of placement, smaller sections, improved finishing and higher strength and durability. For the design of these types of concretes, it is advisable to carry out studies on pastes or mortars in order to evaluate admixture - cementitious material compatibility. This evaluation entails verifying fresh state properties and evolution over time. The aim of this work is to evaluate the behavior of mortars made with different water reducers as well as binary and ternary cements, and their connection to the properties they acquire in hardened state. Fluidity in the fresh state and absorption, density and compressive strength in the hardened state were evaluated. The results show that the impact of superplasticizers is not restricted to the fresh state, as influence on the development of the degree of hydration and compacity can also be noticed. La elaboración de hormigones de alta performance ofrece beneficios tales como mayor facilidad de colocación, secciones reducidas, mejoras en la terminación, mayor durabilidad y resistencia comparativamente con hormigones convencionales. Para el diseño de dichos hormigones, es aconsejable realizar estudios en pastas o morteros para evaluar la compatibilidad aditivo reductor de agua-material cementiceo. Dicha evaluación implica la verificación de propiedades del estado fresco y su evolución en el tiempo. El objetivo de este estudio consiste en evaluar el comportamiento de diferentes sistemas aditivo reductor de agua-cemento en morteros elaborados con diferentes cementos binarios y ternarios y su conexión con las propiedades del estado endurecido. La fluidez en estado fresco, densidad, absorción y resistencia a compresión en estado endurecido fueron evaluadas. De los resultados obtenidos surge que la influencia de los superplastificantes no es restringida al estado fresco, observándose también influencia en el desarrollo del grado de hidratación y en la compacidad. Fil: Sosa, Maria Eva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Laboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológica; Argentina Fil: Villagrán Zaccardi, Yury Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Laboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológica; Argentina Fil: Peralta, Juan Pablo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Laboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Zega, Claudio Javier. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Laboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina

Background Durable mechanical support devices are prohibitively expensive in our health system and may be unsuitable for critically ill patients. CentriMag is an alternative bridge to transplantation or recovery. Methods We retrospectively reviewed 28 patients (23 males) aged 13–60 years who received CentriMag support. The etiology was ischemic in 13 (46%), dilated cardiomyopathy in 8 (29%), and others in 7 (25%). All patients were in Interagency Registry for Mechanically Assisted Circulatory Support class I, and 27 (96%) had multiorgan failure; 2 (7%) were post-cardiotomy and 12 (43%) had a previous cardiac arrest (mean arrest time 21 ± 17 min). Results Thirty-day post-implant survival was 79% (22 patients). Twenty (71%) patients were successfully bridged to transplantation or recovery. The mean support time was 40 days; 12 (43%) patients had >4-weeks’ support (longest was 292 days). Eight (29%) patients died on support. Complications included bleeding in 10 (36%) cases, immediate stroke in 4 (14%), and dialysis in 8 (29%). There was no stroke during subsequent support. Eighteen (64%) patients underwent transplantation, and 17 of them were discharged. Two (7%) patients recovered and were discharged. Two-year survival was 62% ± 10%. Mean follow-up was 21 months (total follow-up 579 months). Two (7%) patients died during follow-up. All survivors were in New York Heart Association class I. Conclusions CentriMag is useful for medium-term support for cardiogenic shock in a developing country. Support for >4 weeks is feasible. The stroke rate is low during support. The major drawback is prolonged intensive care unit stay.

On June 04, 2020, Chile had 113,628 cases COVID-19, 1275 deaths, 1450 patients were on invasive mechanical ventilation (IMV). The objective was describing the characteristics on admission and their relationship with the condition at discharge of patients with positive real-time polymerase chain reaction test for SARS CoV-2 (RT-PCR) in a tertiary health center. Methods: Retrospective and observational cohort study of 529 consecutive patients with positive RT-PCR for SARS CoV-2, discharged between March 14 and June 4, 2020 from Clinica Davila, Santiago. Demographic data, laboratory tests, Quality Adjusted Life Years (QALY), medical insurance, ventilatory assistance, and discharge condition were collected. Differences were evaluated by chi-square test, student’s t test, or Mann–Whitney U test. Logistic regression analysis was performed to identify variables that were predictive of condition at discharge. Results: A total of 529 patients were included (median age, 49 years [interquartile range {IQR}, 37-62; range, 0-97 years]; 45% women). The most common comorbidities were hypertension (171, 32.3%) and diabetes mellitus (98, 18.5%), On admission 352 patients (66.5%) had respiratory symptoms and 177 (33.4%) had other symptoms or other diagnoses. The median (IQR) PaO2 / FiO2 on admission of survivors, non-survivors and transferred were 316 (261-360), 167 (80-268) and 212 (130-261) respectively. At discharge, 448 (84.7%) were survivors, 54 (10.2%) non-survivors, and 27 (5.1%) were transferred to other centers. Median age of survivors and non-survivors was 46 (36-59) and 75.5 (66-84) years. Of the 116 patients (21,9%) who received support ventilation, 67 were discharged alive (57.8%), 28 died (24%), and 21 (18%) were transferred to another hospital. The variables associated with risk of death were: age ≥ 60 years (OR 15.3; 95% CI: 7.25–32.2; P = 0.001); QALY score ≤ 15 points (OR 14.01; 95% CI: 4.82 -40.67; P = 0.001); state health insurance (OR, 2.82; 95% CI: 1.38–5.77; P = 0.004); PaO2 / FiO2 on admission ≤ 200 (OR 5.2; 95% CI: 1.94-13.94; P = 0.001) and high sensitivity T Troponin ≥ 15 ng / L (OR 5.16; 95% CI: 1.95-13.64; P = 0.001). Conclusions: this cohort showed that on admission COVID-19 patients, the PaO2 / FiO2, creatinine and high sensitivity T troponin at the described cut-off points had prognostic value. At discharge, the non-survivors were the older, most often had state health insurance and their QALY scores were significantly lower.

We study the evolution of the force exerted by a granular column on the bottom surface of a silo during its discharge. Previous to the discharge, we prepare the system using different filling procedures: distributed, i.e. a homogeneous rain of grains across the cross-section of the silo; concentric, a granular jet along the silo axis; and a combination of both, i.e. filling half of the silo using one procedure and the second half using the other. We observe that each filling protocol leads to distinctive evolutions of the apparent mass (i.e., the effective weight sensed at the base) during the discharge. Interestingly, the use of combined filling protocols may lead to a reduced apparent mass, smaller than any other achieved with a simple filling. We propose a model based on the Janssen rationale that quantitatively accounts for the latter puzzling experimental observation. Fil: Peralta, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional; Argentina Fil: Aguirre, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; Argentina. LIA PMF-FMF; Argentina. LIA PMF-FMF; Francia Fil: Géminard, Jean-Christophe. LIA PMF-FMF; Argentina. LIA PMF-FMF; Francia. Centre National de la Recherche Scientifique; Francia Fil: Pugnaloni, Luis Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; Argentina

The “faster-is-slower” (FIS) effect was first predicted by computer simulations of the egress of pedestrians through a narrow exit [D. Helbing, I. J. Farkas, and T. Vicsek, Nature (London) 407, 487 (2000)]. FIS refers to the finding that, under certain conditions, an excess of the individuals' vigor in the attempt to exit causes a decrease in the flow rate. In general, this effect is identified by the appearance of a minimum when plotting the total evacuation time of a crowd as a function of the pedestrian desired velocity. Here, we experimentally show that the FIS effect indeed occurs in three different systems of discrete particles flowing through a constriction: (a) humans evacuating a room, (b) a herd of sheep entering a barn, and (c) grains flowing out a 2D hopper over a vibrated incline. This finding suggests that FIS is a universal phenomenon for active matter passing through a narrowing. Fil: Pastor, Jose. Universidad de Navarra. Facultad de Ciencias. Departamento de Física y Matemática Aplicada; España Fil: Garcimartín, A. Universidad de Navarra. Facultad de Ciencias. Departamento de Física y Matemática Aplicada; España Fil: Gago, Paula. UTN (Universidad Tecnológica Nacional). Departamento de Ingeniería Mecánica; Argentina Fil: Peralta, Juan. UTN (Universidad Tecnológica Nacional). Departamento de Ingeniería Mecánica; Argentina Fil: Martin Gomez, Cesar. Universidad de Navarra. Escuela Técnica Superior de Arquitectura. Departamento de Construcción, Instalaciones y Estructuras; España Fil: Ferrer, Luis. Universidad de Zaragoza. Facultad de Veterinaria. Departamento de Patología Animal; España Fil: Maza, Diego. Universidad de Navarra. Departamento de Física; España Fil: Parisi, D. Instituto Tecnológico de Buenos Aires. CONICET; Argentina Fil: Pugnaloni, Luis. UTN (Universidad Tecnológica Nacional). Departamento de Ingeniería Mecánica. GMG. CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas); Argentina Fil: Zuriguel, Iker. Universidad de Navarra. Facultad de Ciencias. Departamento de Física y Matemática Aplicada; España

When a large set of discrete bodies passes through a bottleneck, the flow may become intermittent due to the development of clogs that obstruct the constriction. Clogging is observed, for instance, in colloidal suspensions, granular materials and crowd swarming, where consequences may be dramatic. Despite its ubiquity, a general framework embracing research in such a wide variety of scenarios is still lacking. We show that in systems of very different nature and scale -including sheep herds, pedestrian crowds, assemblies of grains, and colloids- the probability distribution of time lapses between the passages of consecutive bodies exhibits a power-law tail with an exponent that depends on the system condition. Consequently, we identify the transition to clogging in terms of the divergence of the average time lapse. Such a unified description allows us to put forward a qualitative clogging state diagram whose most conspicuous feature is the presence of a length scale qualitatively related to the presence of a finite size orifice. This approach helps to understand paradoxical phenomena, such as the faster-is-slower effect predicted for pedestrians evacuating a room and might become a starting point for researchers working in a wide variety of situations where clogging represents a hindrance. Fil: Zuriguel, Iker. Universidad de Navarra. Facultad de Ciencias. Departamento de Física y Matemática Aplicada; España Fil: Parisi, Daniel. Instituto Tecnológico de Buenos Aires. CONICET; Argentina Fil: Cruz Hidalgo, Raul. Universidad de Navarra. Facultad de Ciencias. Departamento de Física y Matemática Aplicada; España Fil: Lozano, Celia. Universidad de Navarra. Facultad de Ciencias. Departamento de Física y Matemática Aplicada; España Fil: Janda, Alvaro. University of Edinburgh. School of Engineering; UK Fil: Gago, Paula. UTN (Universidad Tecnológica Nacional). Departamento de Ingeniería Mecánica; Argentina Fil: Peralta, Juan. UTN (Universidad Tecnológica Nacional). Departamento de Ingeniería Mecánica; Argentina Fil: Ferrer, Luis. Universidad de Zaragoza. Facultad de Veterinaria. Departamento de Patología Animal; España Fil: Pugnaloni, Luis. UTN (Universidad Tecnológica Nacional). Departamento de Ingeniería Mecánica. GMG. CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas); Argentina Fil: Clement, Eric. Univ. P.& M. Curie and Paris-Diderot. PMMH-ESPCI; France Fil: Maza, Diego. Universidad de Navarra. Departamento de Física; España Fil: Pagonabarraga, Ignacio. Universitat de Barcelona. Departament de Fisica Fonamental; España Fil: Garcimartín, A. Universidad de Navarra. Facultad de Ciencias. Departamento de Física y Matemática Aplicada; España

Introduction: Heart transplantation is the therapy of choice for advance heart failure. Our group developed two transplant programs at Instituto Nacional del Tórax and Clínica Dávila. We report our clinical experience based on distinctive clinical policies. Patients and Methods: Fifty-three consecutive patients were transplanted between November 2008 and April 2013, representing 51% of all Chilean cases. Distinctive clinical policies include intensive donor management, generic immunosuppression and VAD (ventricular assist devices) insertion. Results: Ischemic or dilated cardiomyopathy were the main indications (23 (43%) each), age 48 ± 13 years and 48 (91%) were male. Transplant listing Status: IA 14 (26%) (VAD or 2 inotropes), IB 14 (26%) (1 inotrope) and II25 (47%) (no inotrope). Mean waiting time 70 ± 83 days. Twelve (24%) were transplanted during VAD support (median support: 36 days). Operative technique: orthotopic bicaval transplant with ischemia time: 175 ± 54 min. Operative mortality: 3 (6%), all due to right ventricular failure. Re-exploration for bleeding 2 (4%), stroke 3 (6%), mediastinitis 0 (0%), pneumonia 4 (8%), and transient dialysis 6 (11%). Mean follow-up was 21 ± 14 months. Three-year survival was 86 ± 6%. One patient died of Pneumocystis jirovecii pneumonia and the other died suddenly (non-compliance). Freedom from rejection requiring specific therapy was 80 ± 7% at 3 years of follow-up. Four hundred eighty four endomyocardial biopsies were done: 11 (2.3%) had 2R rejection. All survivors are in NYHA (New York Heart Association) functional class I and all but one have normal biventricular function. Conclusion: Mid-term results are similar to those reported by the registry of the International Society for Heart and Lung Transplantation. This experience has a higher proportion of VAD support than previous national series. Rejection rates are low in spite of generic immunosuppression.

Heart transplantation is the therapy of choice for advance heart failure. Our group developed two transplant programs at Instituto Nacional del Tórax and Clínica Dávila. We report our clinical experience based on distinctive clinical policies.Fifty-three consecutive patients were transplanted between November 2008 and April 2013, representing 51% of all Chilean cases. Distinctive clinical policies include intensive donor management, generic immunosuppression and VAD (ventricular assist devices) insertion.Ischemic or dilated cardiomyopathy were the main indications (23 (43%) each), age 48 ± 13 years and 48 (91%) were male. Transplant listing Status: IA 14 (26%) (VAD or 2 inotropes), IB 14 (26%) (1 inotrope) and II25 (47%) (no inotrope). Mean waiting time 70 ± 83 days. Twelve (24%) were transplanted during VAD support (median support: 36 days).orthotopic bicaval transplant with ischemia time: 175 ± 54 min. Operative mortality: 3 (6%), all due to right ventricular failure. Re-exploration for bleeding 2 (4%), stroke 3 (6%), mediastinitis 0 (0%), pneumonia 4 (8%), and transient dialysis 6 (11%). Mean follow-up was 21 ± 14 months. Three-year survival was 86 ± 6%. One patient died of Pneumocystis jirovecii pneumonia and the other died suddenly (non-compliance). Freedom from rejection requiring specific therapy was 80 ± 7% at 3 years of follow-up. Four hundred eighty four endomyocardial biopsies were done: 11 (2.3%) had 2R rejection. All survivors are in NYHA (New York Heart Association) functional class I and all but one have normal biventricular function.Mid-term results are similar to those reported by the registry of the International Society for Heart and Lung Transplantation. This experience has a higher proportion of VAD support than previous national series. Rejection rates are low in spite of generic immunosuppression.

Cardiogenic shock after myocardial infarction has a high mortality even if early revascularization is achieved. Biventricular assist devices have not been used in Chile in this critical setting. We report a case of a 55-year-old diabetic man who suffered an acute chest pain and ventricular fibrillation. Prompt outside hospital defibrillation/reanimation restored pulse and allowed emergency room transfer on mechanical ventilation. Electrocardiogram showed an anterior myocardial infarction and early revascularization was achieved by anterior descending artery angioplasty. However, severe cardiogenic shock continued in spite of inotropic and intra aortic balloon pump support. Levitronix Centrimag biventricular mechanical circulatory support was inserted during reanimation for recurrent ventricular fibrillation and the patient listed for urgent cardiac transplantation upon stabilization. Heart transplantation was performed successfully 28 days later and the patient was discharged after a 21-day recovery period. Twelve months after transplant the patient is in NYHA functional class I with normal biventricular function. Levitronix Centrimag biventricular mechanical circulatory support could be used successfully as a bridge-to-transplant for myocardial infarction cardiogenic shock.

Introduction. Myocardial infarction cardiogenic shock portends a high mortality even if early revascularization is achieved. Biventricular assist devices have not been used in Chile in this critical setting. Methods/Results. We report a case of a 55 year-old diabetic man who suffered an acute chest pain and ventricular fibrillation. Prompt out-side hospital cardioversion/reanimation restored pulse and allowed emergency room transfer on mechanical ventilation. Electrocardiogram showed an anterior myocardial infarction and early revascularization was achieved by anterior descending artery angioplasty. However, severe cardiogenic shock continued in spite of inotropic and intraortic balloon pump support. LEVITRONIX CENTRIMAG® biventricular mechanical circulatory support was inserted during reanimation for recurrent ventricular fibrillation and the patient listed for urgent cardiac transplantation upon stabilization. Heart transplantation was performed successfully 28 days later and the patient dismissed after a 21-day recovery period. Six months after transplant patient is in NYHA functional class I with normal biventricular function. Conclusion. LEVITRONIX CENTRIMAG® biventricular mechanical circulatory support could be used successfully as a bridge-to-transplant for myocardial infarction cardiogenic shock. This is the longest biventricular circulatory support reported in Chile .