Estudio de las limitantes por torsión impuestas al método simplificado de análisis

89 páginas. Maestría en Ingeniería Estructural.El método simplificado de análisis es ampliamente utilizado en estructuras de mampostería, ya que permite realizar el diseño y análisis de una manera rápida y aproximada, por lo que este método desprecia aspectos tales como, la flexibilidad de diafragma, los efectos de torsión, los efectos bidireccionales, los momentos de volteo y los desplazamientos horizontales. En general, el método simplificado de análisis verifica únicamente que en cada piso la suma de las resistencias al corte de los muros de carga, en la dirección de la aceleración, sea cuando menos igual a la fuerza cortante que obre en dicho piso. No se debe dejar de mencionar los antecedentes del método simplificado. Se necesita tener un conocimiento amplio del método simplificado de análisis, ya que este método será una de las bases más importantes para realizar nuestros estudios. Se mencionará por tanto, los requisitos indispensables y únicos para utilizar el método simplificado de análisis basado en las Normas Técnicas Complementarias por Sismo 2004 (NTCS-2004 2004). Un objetivo a cumplir para la presente tesis, es el estudiar las limitantes por torsión asociadas al método simplificado 2004, como parte del trabajo de investigación analítico en curso. Por lo que se realizó una extensa recopilación de trabajos encontrados en la literatura, relacionados con este tema. Esto es muy necesario, ya que se necesita saber y entender los análisis que se han efectuado para estudiar los efectos por torsión en las estructuras

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

Prevalence of DRESS Syndrome

DRESS syndrome (Drug rash with Eosinophilia and Systemic Symptoms) is an idiosyncratic reaction (type B), characterized by peripheral eosinophilia and systemic symptoms, such as fever, rash, lymphadenopathy, hepatitis, atypical lymphocytes and elevation of liver enzymes at least twice its normal level or increase of alanine amino transferase (ALT) >100 U/L. Its incidence is of 1/1,000 to 10,000 exposures and its mortality is of 10%-20%. Treatment is based on steroids and on the suspension of the suspect drug. This paper reports the cases of six patients with DRESS syndrome attended at Centro Medico Nacional Siglo XXI, Mexico City, from September 2012 to September 2013, which accounted for 12.5% of patients attended with adverse reactions to drugs