Evaluación y Comparación de dos Sistemas de Cánula Nasal de Alto Flujo Artesanales / Evaluation and Comparison of Two Artisan alternative of High Flow Nasal Cannula Systems

Introducción: Una de las estrategias principales de atención para los pacientes con infección por SARS-CoV2 es el soporte respiratorio, incluida la terapia de oxígeno para pacientes con hipoxemia, en la que se ha informado que la cánula nasal de alto flujo (CNAF) es efectiva para mejorar la oxigenación, existiendo reportes de disminución en la intubación en pacientes con insuficiencia respiratoria hipoxémica aguda, en comparación con dispositivos de oxigenoterapia convencional. Dada la falta de insumos y equipos durante el periodo de pandemia, han surgido diversas formas de construir de manera artesanal equipos de alto flujo. Objetivo: Medir y comparar dos sistemas de alto flujo artesanales, en relación con su rendimiento teórico, en la entrega real de flujo total y en la fracción inspirada de oxígeno (FiO2). Métodos: Se confeccionaron dos modelos de CNAF artesanales. El primer equipo (CNAF-A) se confeccionó utilizando 2 flujómetros de aire y un flujómetro de oxígeno unidos a un conector que recibe los flujos provenientes de los 3 flujómetros mencionados y cuya mezcla de aire pasa por un sistema de termo-humidificación. El segundo modelo (CNAF-B) se construyó usando un inyector de un equipo de oxigenoterapia de concentración variable (tipo "Venturi"), conectado a un flujómetro de oxígeno, en donde se realiza una mezcla con aire ambiental para entregar un flujo final y una concentración de oxígeno determinada. Se confeccionaron 10 equipos de cada modelo de sistema de CNAF artesanal. Se evaluó el flujo final y la FiO2 entregada por cada CNAF. Los resultados obtenidos fueron comparados con los valores teóricos que debiera entregar cada equipo de CNAF artesanal y se evaluó la correlación entre los valores medidos. Resultados: Se observó una baja correlación entre el flujo esperado teórico y el flujo medido. Resultados similares se encontraron al evaluar valores teóricos y medidos de FiO2. El modelo CNAF-A demostró generar flujos mas altos de lo esperado logrando cumplir con niveles requeridos para considerarse un sistema de alto flujo. El sistema CNAF-B entregó flujos significativamente menores a los valores esperados. Conclusiones: Ambos modelos de CNAF presentan bajo nivel de concordancia con sus valores teóricos, tanto en la FiO2 como en el flujo entregado. Sin embargo, la CNAF-A se logra comportar como sistema de alto flujo. Un sistema de CNAF confeccionado con un sistema Venturi no es suficiente para generar terapia de alto flujo.

Introduction: One of the main care strategies for patients with SARS-CoV2 infection is respiratory support, including oxygen therapy for patients with hypoxemia, in which the high-flow nasal cannula (CNAF) has been reported to be effective to improve oxygenation, there are reports of decreased intubation in patients with acute hypoxemic respiratory failure, compared to conventional oxygen therapy devices. Given the lack of supplies and equipment during the pandemic period, various ways have emerged to build high-flow equipment by hand. Objective: Measure and compare two artisanal high-flow systems, in relation to their theoretical performance, in the actual delivery of total flow and in the fraction of inspired oxygen (FiO2). Methods: Two models of artisanal CNAF were made. The first equipment (CNAF-A) was made using 2 air flow meters and an oxygen flow meter connected to a connector that receives the flows from the 3 mentioned flow meters and whose air mixture passes through a thermo-humidification system. The second model (CNAF-B) was built using an injector of a variable concentration oxygen therapy equipment ("Venturi" type), connected to an oxygen flow meter, where a mixture is made with ambient air to deliver a final flow and a given oxygen concentration. 10 kits of each model of the artisanal CNAF system were made. The final flow and the FiO2 delivered by each CNAF were evaluated. The results obtained were compared with the theoretical values ​​that each artisanal CNAF equipment should deliver and the correlation between the measured values ​​was evaluated. Results: A low correlation was observed between the theoretical expected flow and the measured flow. Similar results were found when evaluating theoretical and measured FiO2 values. The CNAF-A model proved to generate higher flows than expected, achieving the required levels to be considered a high flow system. The CNAF-B system delivered flows significantly lower than the expected values. Conclusions: Both CNAF models show a low level of agreement with their theoretical values, both in FiO2 and in the delivered flow. However, CNAF-A manages to behave as a high-flux system. A CNAF system made with a Venturi system is not sufficient to generate high-flow therapy.

Correlación de la Escala de Kellgren-Lawrence con la Clasificación de Outerbridge en Pacientes con Gonalgia Crónica / Correlation of the Kellgren-Lawrence Scale with the Outerbridge Classification in Patients with Chronic Gonalgia

Introducción La correlación entre las escalas radiográficas y artroscópicas para el grado de lesión articular en pacientes con osteoartritis (OA) es inconsistente. El estudio busca determinar la correlación entre el grado de lesión articular según la escala radiográfica de Kellgren-Lawrence (KL) y la clasificación artroscopica de Outerbridge (CO). Materiales y Métodos Se analizaron pacientes adultos (>18 años) con gonalgia crónica realizando una valoración de las radiografía de rodilla según la escala KL. Posteriormente, los mismos pacientes fueron sometidos a artroscopía en donde se valoró el grado de lesión condral de acuerdo a la CO. Se realizó una correlación de Spearman entre las escalas de clasificación. Se calculó la sensibilidad, especificidad, valor predictivo positivo, valor predictivo negativo de la radiografía para diagnosticar OA (grado >1 en la CO). Resultados Se analizaron 80 pacientes, 52.5% fueron mujeres. La clasificación radiográfica KL mostró una sensibilidad promedio de 90.2%, especificidad de 24.6%, VPP de 86.3% y VPN de 32.0% para diagnosticar cualquier grado de OA en relación a la CO. En promedio, se encontró una correlación moderada a baja (Rho 0.40, p<0.001) entre la escala de KL y la CO. El porcentaje de correspondencia entre los grados de KL y CO fue de 17.5% en promedio. Discusión La clasificación KL es sensible para diagnosticar OA en rodillas, sin embargo, nuestro estudio sugiere que es poco específica y presenta una moderada correlación con los grados de lesión diagnosticados mediante artroscopía utilizando la CO. Nivel de evidencia

Background The correlation between radiographic and arthroscopic scales for the degree of joint injury in patients with osteoarthritis (OA) is inconsistent. The study seeks to determine the correlation between the degree of joint injury according to the Kellgren-Lawrence (KL) radiographic scale and the Outerbridge (CO) arthroscopic classification. Methods Adult patients (> 18 years) with chronic gonalgia were analyzed by evaluating the knee radiographs according to the KL scale. Subsequently, the same patients underwent arthroscopy where the degree of chondral injury was assessed according to CO. A Spearman correlation was made between the rating scales. Sensitivity, specificity, positive predictive value, negative predictive value of radiography to diagnose OA (grade>1 in CO) were calculated. Results 80 patients were analyzed, 52.5% were women. The KL radiographic classification showed an average sensitivity of 90.2%, specificity of 24.6%, PPV of 86.3% and NPV of 32.0% to diagnose any degree of OA in relation to CO. On average, a moderate to low correlation (Rho 0.40, p <0.001) was found between the KL scale and the CO. The percentage of correspondence between the grades of KL and CO was 17.5% on average. Discussion The KL classification is sensitive for diagnosing OA in the knees, however, our study suggests that it is not very specific and has a moderate correlation with the degrees of injury diagnosed by arthroscopy using CO. Evidence Level IV.

Cinnamic acid, ethanol and temperature interaction on coumarate decarboxylase activity and the relative expression of the putative cd gene in D. bruxellensis

Dekkera bruxellensis is one of the main contaminating yeasts in wine due to its ability to metabolize cinnamic acids into volatile phenols. This yeast metabolizes p-coumaric acid into 4-vinylphenol through a coumarate decarboxylase (CD) and then transforms it into to 4-ethylphenol (EF) through a vinylphenol reductase. In this work we investigated the influence of the interaction between the concentration of p-coumaric acid, ferulic acid and ethanol as well as growth temperature on the production of CD activity and the expression of a putative gene that codes for this enzymatic activity. For this, a Box Behnken experimental design was used. The concentration of p-coumaric acid (5-26 ppm) and ferulic acid (3-9 ppm) alone did not show any significant effect on any of the studied response variables. However, the interaction between (ethanol concentration * cinnamic acid concentration) and (ethanol concentration * temperature) had a significant statistical effect on the production of CD activity. Additionally, a higher growth temperature negatively affected the expression of the putative cd gene and the production of CD activity. This is the first work that studies the effect of cinnamic acids on the production of CD activity and the relative expression of its putative gene, using natural concentrations of cinnamic acid found in wine.