Cánula Nasal de Alto Flujo Asimétrica: una Revisión Narrativa / Asymmetrical High Flow Nasal Cannula: a Narrative Review

Los sistemas de Cánula nasal de alto flujo (CNAF) han sido ampliamente utilizados en el campo clínico como soporte no invasivo en el manejo de la falla respiratoria aguda (sobre todo hipoxémica) y cuidados post extubación. Clínica y fisiológicamente, las cánulas nasales de alto flujo son capaces de entregar un flujo de oxigeno alto que, debido a que ese gas se encuentra optimamente humidificado y calefaccionado, permite una mejor tolerancia por parte del paciente al ser comparada con las cánulas de oxigeno tradicionales. Por otra parte, este alto. Flujo es capaz de generar una presión positiva al final de la espiración (CPAP) en la vía área y favorecer tanto en barrido de dióxido de carbono (CO2) desde la vía aérea superior, lo que disminuye el trabajo respiratorio del paciente y mejora su confort.. Sin embargo; aún existe un alto porcentaje de pacientes que fracasan la terapia con CNAF y requiere soportes mas complejos como la ventilación mecánica, ya sea imvasiva o no. Estos resultados con la terapia CNAF pueden ser influidos por aspectos técnicos como, por ejemplo, la turbulencia que pueden generar estos sistemas a nivel de la región nasal. Por esta razón se han desarrollado nuevas tecnologías en el diseño y uso de interfaces para suministrar este alto flujo. Una de estas innovaciones es el uso de cánulas asimétricas, las que potencian los beneficios fisiológicos que entrega una cánula de alto flujo convencional. La presente revisión pretende exponer las principales diferencias que presenta el sistema de alto flujo convencional versus la nueva interface asimétrica.

High-flow nasal cannula (HFNC) systems have been widely used in the clinical field as non-invasive support in the management of acute respiratory failure (especially hypoxemic) and post-extubation care. Clinically and physiologically, high flow nasal cannulas are capable of delivering a high flow of oxygen which, because this gas is optimally humidified and heated, allows better tolerance by the patient when compared to traditional oxygen cannulas. . On the other hand, this high. Flow is capable of generating positive pressure at the end of expiration (CPAP) in the airway and favoring the sweep of carbon dioxide (CO2) from the upper airway, which reduces the patient's respiratory work and improves their comfort. .. However; There is still a high percentage of patients who fail therapy with HFNC and require more complex supports such as mechanical ventilation, whether invasive or not. These results with HFNC therapy can be influenced by technical aspects such as, for example, the turbulence that these systems can generate in the nasal region. For this reason, new technologies have been developed in the design and use of interfaces to provide this high flow. One of these innovations is the use of asymmetric cannulas, which enhance the physiological benefits provided by a conventional high-flow cannula. The present review aims to expose the main differences that the conventional high flow system presents versus the new asymmetric interface.

Specific Training Improves the Detection and Management of Patient-Ventilator Asynchrony.

BACKGROUND: Patient-ventilator asynchrony is common in patients undergoing mechanical ventilation. The proportion of health-care professionals capable of identifying and effectively managing different types of patient-ventilator asynchronies is limited. A few studies have developed specific training programs, but they mainly focused on improving patient-ventilator asynchrony detection without assessing the ability of health-care professionals to determine the possible causes. METHODS: We conducted a 36-h training program focused on patient-ventilator asynchrony detection and management for health-care professionals from 20 hospitals in Latin America and Spain. The training program included 6 h of a live online lesson during which 120 patient-ventilator asynchrony cases were presented. After the 6-h training lesson, health-care professionals were required to complete a 1-h training session per day for the subsequent 30 d. A 30-question assessment tool was developed and used to assess health-care professionals before training, immediately after the 6-h training lecture, and after the 30 d of training (1-month follow-up). RESULTS: One hundred sixteen health-care professionals participated in the study. The median (interquartile range) of the total number of correct answers in the pre-training, post-training, and 1-month follow-up were significantly different (12 [8.75-15], 18 [13.75-22], and 18.5 [14-23], respectively). The percentages of correct answers also differed significantly between the time assessments. Study participants significantly improved their performance between pre-training and post-training (P < .001). This performance was maintained after a 1-month follow-up (P = .95) for the questions related to the detection, determination of cause, and management of patient-ventilator asynchrony. CONCLUSIONS: A specific 36-h training program significantly improved the ability of health-care professionals to detect patient-ventilator asynchrony, determine the possible causes of patient-ventilator asynchrony, and properly manage different types of patient-ventilator asynchrony.

Pendelluft in hypoxemic patients resuming spontaneous breathing: proportional modes versus pressure support ventilation.

BACKGROUND: Internal redistribution of gas, referred to as pendelluft, is a new potential mechanism of effort-dependent lung injury. Neurally-adjusted ventilatory assist (NAVA) and proportional assist ventilation (PAV +) follow the patient's respiratory effort and improve synchrony compared with pressure support ventilation (PSV). Whether these modes could prevent the development of pendelluft compared with PSV is unknown. We aimed to compare pendelluft magnitude during PAV + and NAVA versus PSV in patients with resolving acute respiratory distress syndrome (ARDS). METHODS: Patients received either NAVA, PAV + , or PSV in a crossover trial for 20-min using comparable assistance levels after controlled ventilation (> 72 h). We assessed pendelluft (the percentage of lost volume from the non-dependent lung region displaced to the dependent region during inspiration), drive (as the delta esophageal swing of the first 100 ms [ΔPes 100 ms]) and inspiratory effort (as the esophageal pressure-time product per minute [PTPmin]). We performed repeated measures analysis with post-hoc tests and mixed-effects models. RESULTS: Twenty patients mechanically ventilated for 9 [5-14] days were monitored. Despite matching for a similar tidal volume, respiratory drive and inspiratory effort were slightly higher with NAVA and PAV + compared with PSV (ΔPes 100 ms of -2.8 [-3.8--1.9] cm H2O, -3.6 [-3.9--2.4] cm H2O and -2.1 [-2.5--1.1] cm H2O, respectively, p < 0.001 for both comparisons; PTPmin of 155 [118-209] cm H2O s/min, 197 [145-269] cm H2O s/min, and 134 [93-169] cm H2O s/min, respectively, p < 0.001 for both comparisons). Pendelluft magnitude was higher in NAVA (12 ± 7%) and PAV + (13 ± 7%) compared with PSV (8 ± 6%), p < 0.001. Pendelluft magnitude was strongly associated with respiratory drive (ß = -2.771, p-value < 0.001) and inspiratory effort (ß = 0.026, p < 0.001), independent of the ventilatory mode. A higher magnitude of pendelluft in proportional modes compared with PSV existed after adjusting for PTPmin (ß = 2.606, p = 0.010 for NAVA, and ß = 3.360, p = 0.004 for PAV +), and only for PAV + when adjusted for respiratory drive (ß = 2.643, p = 0.009 for PAV +). CONCLUSIONS: Pendelluft magnitude is associated with respiratory drive and inspiratory effort. Proportional modes do not prevent its occurrence in resolving ARDS compared with PSV.

Dynamic relative regional lung strain estimated by computed tomography and electrical impedance tomography in ARDS patients.

BACKGROUND: In the acute distress respiratory syndrome (ARDS), specific lung regions can be exposed to excessive strain due to heterogeneous disease, gravity-dependent lung collapse and injurious mechanical ventilation. Computed tomography (CT) is the gold standard for regional strain assessment. An alternative tool could be the electrical impedance tomography (EIT). We aimed to determine whether EIT-based methods can predict the dynamic relative regional strain (DRRS) between two levels of end-expiratory pressure (PEEP) in gravity-non-dependent and dependent lung regions. METHODS: Fourteen ARDS patients underwent CT and EIT acquisitions (at end-inspiratory and end-expiratory) at two levels of PEEP: a low-PEEP based on ARDS-net strategy and a high-PEEP titrated according to EIT. Three EIT-based methods for DRRS were compared to relative CT-based strain: (1) the change of the ratio between EIT ventilation and end-expiratory lung impedance in arbitrary units ([ΔZAU low-PEEP/EELIAU low-PEEP]/[ΔZAU high-PEEP/EELIAU high-PEEP]), (2) the change of ΔZ/EELI ratio calibrated to mL ([ΔZml low-PEEP/EELIml low-PEEP]/[ΔZml high-PEEP/EELIml high-PEEP]) using CT data, and (3) the relative change of ∆ZAU (∆ZAU low-PEEP/∆ZAU high-PEEP). We performed linear regressions analysis and calculated bias and limits of agreement to assess the performance of DRRS by EIT in comparison with CT. RESULTS: The DRRS assessed by (ΔZml low-PEEP/EELIml low-PEEP)/(ΔZml high-PEEP/EELIml high-PEEP) and ∆ZAU low-PEEP/∆ZAU high-PEEP showed good relationship and agreement with the CT method (R2 of 0.9050 and 0.8679, respectively, in non-dependent region; R2 of 0.8373 and 0.6588, respectively, in dependent region; biases ranging from - 0.11 to 0.51 and limits of agreement ranging from - 0.73 to 1.16 for both methods and lung regions). Conversely, DRRS based on EELIAU ([ΔZAU low-PEEP/EELIAU low-PEEP]/[ΔZAU high-PEEP/EELIAU high-PEEP]) exhibited a weak negative relationship and poor agreement with the CT method for both non-dependent and dependent regions (R2 ~ 0.3; bias of 3.11 and 2.08, and limits of agreement of - 2.13 to 8.34 and from - 1.49 to 5.64, respectively). CONCLUSION: Changes in DRRS during a PEEP trial in ARDS patients could be monitored using EIT, based on changes in ΔZmL/EELIml and ∆ZAU. The relative change ∆ZAU offers the advantage of not requiring CT data for calibration.

Evaluación del Rendimiento y Producción de Humedad de los Humidificadores de Burbuja usados con Mascarillas Oxígeno de Concentración Variable / Evaluation of the Performance and Humidity Production of Bubble Humidifiers used with Variable Concentration Oxygen Masks

Introducción. Introducción. El uso de humidificadores de burbuja asociados a equipos de oxigenoterapia es una práctica común en los centros hospitalarios de nuestro país. Sin embargo, no se ha evaluado el aporte real de humedad que entregan estos equipos cuando son usados con sistemas de concentración variable a distintas concentraciones de oxígeno. Además, se han descrito problemas de funcionamiento en la entrega de oxígeno cuando se han ocupado este tipo de humidificador. Objetivo. Determinar el aporte real de humedad que entregan los humidificadores de burbuja al ser usados con sistemas de oxigenoterapia de concentración variable. Métodos. Se evaluaron 10 humidificadores de burbuja, marca Hudson RCI®, con válvula liberadora de presión, los cuales se conectaron a un sistema de oxigenoterapia de concentración variable (Marca Hudson RCI®, modelo MULTI-VENT). La medición de la humedad relativa (HR) se realizó en una cámara de acrílico, donde se conectó el inyector del sistema de oxigenoterapia. Para medir H.R. y temperatura se utilizó un higrómetro digital (Veto®, Italia) y un higrómetro análogo (Hygromat®, Alemania). Cada medición requirió un tiempo de 5 minutos para lograr un valor estable. Se realizaron mediciones de la humedad relativa y temperatura entregada por este sistema, con y sin humidificador, a concentraciones de oxígeno de 0.24, 0.26, 0.28, 0.3, 0.35, 0.4 y 0.5. Resultados. Para las la temperatura, no hubo diferencias entre las mediciones realizadas con y sin humidificador de burbuja. Para la humedad relativa, sólo hubo diferencias estadísticamente significativas a concentraciones de oxígeno altas (> 0.35), pero con escaso cambio en la entrega de humedad absoluta. Cuando se utilizó flujos operativos ≥ 6 L/min se activó la válvula liberadora de presión del humidificador. Conclusión. El uso de humidificadores de burbuja asociados a sistemas de oxigenoterapia de concentración variable no genera un aumento significativo de la humedad entregada a concentraciones bajas de oxigeno, por lo cual se podría prescindir de su uso.

Background. The use of bubble humidifiers associated with oxygen therapy equipment is a common practice in hospitals in our country. However, the real contribution of humidity delivered by these equipments when used with variable concentration systems at different oxygen concentrations has not been evaluated. In addition, operating problems have been described in the delivery of oxygen when this type of humidifier has been used. Objetive. Determine the real contribution of humidity delivered by bubble humidifiers when used with variable concentration oxygen therapy systems. Methods. 10 Hudson RCI® brand bubble humidifiers with a pressure release valve were evaluated, which were connected to a variable concentration oxygen therapy system (Hudson RCI® brand, MULTI-VENT model). The relative humidity (RH) was measured in an acrylic chamber, where the injector of the oxygen therapy system was connected. To measure R.H. and temperature, a digital hygrometer (Veto®, Italy) and an analog hygrometer (Hygromat®, Germany) were used. Each measurement required a time of 5 minutes to achieve a stable value. Measurements of the relative humidity and temperature delivered by this system were made, with and without a humidifier, at oxygen concentrations of 0.24, 0.26, 0.28, 0.3, 0.35, 0.4 and 0.5. Results. For temperature, there were no differences between the measurements made with and without a bubble humidifier. For relative humidity, there were only statistically significant differences at high oxygen concentrations (> 0.35), but with little change in absolute humidity delivery. When operating flows ≥ 6 L/min were used, the humidifier pressure relief valve was activated. Conclusion. The use of bubble humidifiers associated with variable concentration oxygen therapy systems does not generate a significant increase in the humidity delivered at low oxygen concentrations, so their use could be dispensed with.

Riesgo de Retención de Secreciones en Pacientes con Ventilación Mecánica Invasiva / Risk of Retention of Secretions in Patients with Invasive Mechanical Ventilation

Introducción. Los pacientes conectados a ventilación mecánica invasiva pueden presentar complicaciones respiratorias, donde la retención de secreciones es una de las más frecuentes. El drenaje y eliminación de las secreciones depende entre otras variables de los flujos respiratorios generados, donde una diferencia absoluta entre el flujo espiratorio máximo (FEM) y flujo inspiratorio máximo (FIM) menor a 17 L•min-1 o una relación FIM/FEM mayor a 0.9 favorecerían la retención de secreciones. Sin embargo, falta por determinar los flujos respiratorios resultantes y la proporción de pacientes con riesgo de retención de secreciones según estos parámetros. Objetivo. Determinar los flujos respiratorios durante la ventilación mecánica invasiva y la proporción de pacientes que se encuentra en riesgo de retención de secreciones. Métodos. Estudio descriptivo transversal desarrollado en la Unidad de Paciente Crítico Médico-Quirúrgico del "Hospital Clínico de la Red de Salud UC-CHRISTUS". Se incluyeron pacientes adultos intubados y conectados a ventilación mecánica, en quienes se determinó los flujos respiratorios resultantes y se estimó la diferencia absoluta FEM-FIM, la relación FIM/FEM y la proporción de pacientes con riesgo de retención de secreciones. Resultados. Se incluyeron 100 pacientes, 45% presentaba entre sus diagnósticos patología respiratoria. La mediana de la diferencia absoluta entre FEM y FIM fue de 6 L•min-1 (-5 - 14.5) y la mediana de la tasa FIM/FEM de 0.87 (0.7 - 1.13). Un 84% presentó una diferencia absoluta entre FEM y FIM menor a 17 L•min-1, mientras que el 46% presentó una relación FIM/FEM mayor a 0.9. Conclusión. Una alta proporción de pacientes conectados a ventilación mecánica presenta riesgo de retención de secreciones independiente de la presencia o ausencia de patología respiratoria. Se requieren futuras investigaciones para evaluar el impacto de este criterio sobre complicaciones respiratorias.

Background. Patients connected to invasive mechanical ventilation may develop respiratory complications, where retention of secretions is one of the most frequent. The drainage and elimination of the secretions depend on other variables of the respiratory flows generated, where an absolute difference between the peak expiratory flow (PEF) and peak inspiratory flow (PIF) less than 17 L•min-1 or a PIF/PEF ratio greater than 0.9 would favor secretion retention. However, it is necessary to determine the respiratory flows and the proportion of patients, with and without respiratory pathology, with a risk of secretions retention according to these parameters. Objective. Determine respiratory flows during connection to invasive mechanical ventilation and the proportion of patients with and without respiratory pathology at risk of secretions retention. Methods. A descriptive cross-sectional study was conducted in the Medical-Surgical Intensive Care Unit of the "Hospital Clínico de la Red de Salud UC-CHRISTUS". Intubated adult patients connected to mechanical ventilation were included, in whom the respiratory flows were assessed, and the absolute PEF-PIF difference, PIF/PEF ratio, and the proportion of patients with a risk of secretions retention were determined. Results. 100 patients were included, of which 45% presented among their diagnoses acute or chronic respiratory pathology. For the total number of patients, the median of the absolute difference between PEF and PIF was 6 L•min-1 (-5 - 14.5), and the median of the PIF/PEF ratio of 0.87 (0.7 - 1.13). Of the total of patients, 84% presented an absolute difference between PEF and PIF less than 17 L• min-1, while 46% presented a PIF/PEF ratio greater than 0.9. Conclusion. Considering the absolute difference between PEF-PIF and the PIF/PEF ratio, many patients present a risk of secretions retention. However, whether this is associated with severe respiratory complications in patients connected to invasive mechanical ventilation should be clarified in future research.

Association of lung recruitment and change in recruitment-to-inflation ratio from supine to prone position in acute respiratory distress syndrome.

Prone positioning is an evidence-based treatment for patients with moderate-to-severe acute respiratory distress syndrome. Lung recruitment has been proposed as one of the mechanisms by which prone positioning reduces mortality in this group of patients. Recruitment-to-inflation ratio (R/I) is a method to measure potential for lung recruitment induced by a change in positive end-expiratory pressure (PEEP) on the ventilator. The association between R/I and potential for lung recruitment in supine and prone position has not been studied with computed tomography (CT) scan imaging. In this secondary analysis, we sought to investigate the correlation between R/I measured in supine and prone position with CT and the potential for lung recruitment as measured by CT scan. Among 23 patients, the median R/I did not significantly change from supine (1.9 IQR 1.6-2.6) to prone position (1.7 IQR 1.3-2.8) (paired t test p = 0.051) but the individual changes correlated with the different response to PEEP. In supine and in prone position, R/I significantly correlated with the proportion of lung tissue recruitment induced by the change of PEEP. Lung tissue recruitment induced by a change of PEEP from 5 to 15 cmH2O was 16% (IQR 11-24%) in supine and 14.3% (IQR 8.4-22.6%) in prone position, as measured by CT scan analysis (paired t test p = 0.56). In this analysis, PEEP-induced recruitability as measured by R/I correlated with PEEP-induced lung recruitment as measured by CT scan, and could help to readjust PEEP in prone position.

Inflammatory biomarkers and pendelluft magnitude in ards patients transitioning from controlled to partial support ventilation.

The transition from controlled to partial support ventilation is a challenge in acute respiratory distress syndrome (ARDS) patients due to the risks of patient-self-inflicted lung injury. The magnitude of tidal volume (VT) and intrapulmonary dyssynchrony (pendelluft) are suggested mechanisms of lung injury. We conducted a prospective, observational, physiological study in a tertiary academic intensive care unit. ARDS patients transitioning from controlled to partial support ventilation were included. On these, we evaluated the association between changes in inflammatory biomarkers and esophageal pressure swing (ΔPes), transpulmonary driving pressure (ΔPL), VT, and pendelluft. Pendelluft was defined as the percentage of the tidal volume that moves from the non-dependent to the dependent lung region during inspiration, and its frequency at different thresholds (- 15, - 20 and - 25%) was also registered. Blood concentrations of inflammatory biomarkers (IL-6, IL-8, TNF-α, ANGPT2, RAGE, IL-18, Caspase-1) were measured before (T0) and after 4-h (T4) of partial support ventilation. Pendelluft, ΔPes, ΔPL and VT were recorded. Nine out of twenty-four patients (37.5%) showed a pendelluft mean ≥ 10%. The mean values of ΔPes, ΔPL, and VT were - 8.4 [- 6.7; - 10.2] cmH2O, 15.2 [12.3-16.5] cmH2O and 8.1 [7.3-8.9] m/kg PBW, respectively. Significant associations were observed between the frequency of high-magnitude pendelluft and IL-8, IL-18, and Caspase-1 changes (T0/T4 ratio). These results suggest that the frequency of high magnitude pendelluft may be a potential determinant of inflammatory response related to inspiratory efforts in ARDS patients transitioning to partial support ventilation. Future studies are needed to confirm these results.

Desarrollo de ventiladores mecánicos en Chile. Crónica de la iniciativa "Un Respiro para Chile", durante la primera ola de la pandemia COVID-19 / Development of mechanical ventilators in Chile. Chronicle of the initiative "Un Respiro para Chile"

At the beginning of the COVID-19 pandemic in Chile, in March 2020, a projection indicated that a significant group of patients with pneumonia would require admission to an Intensive Care Unit and connection to a mechanical ventilator. Therefore, a paucity of these devices and other supplies was predicted. The initiative "Un respiro para Chile" brought together many people and institutions, public and private. In the course of three months, it allowed the design and building of several ventilatory assistance devices, which could be used in critically ill patients.

Soybean oil organogelled emulsions as oral delivery systems of hydroxytyrosol and hydroxytyrosol alkyl esters.

Water-in-soybean oil organogelled emulsions (OGEs) were formulated as fat replacers and evaluated as delivery systems of hydroxytyrosol (HT, hydrophilic compound), hydroxytyrosol octanoate (HTC18, hydrophobic compound) and hydroxytyrosol decanoate (HTC10, with intermediate hydrophobicity and the highest antioxidant activity measured by conjugated autoxidizable triene assay). OGEs formulated with 55% of water and a ternary blend of candelilla wax, fully hydrogenated palm oil and monoacylglycerols showed mechanical properties similar to lard and solid-like behavior. The increase in the water content, together with a higher concentration of structuring agents in the oil phase, led to an increase in oil retention capacity and texture parameters. A slight desesterification of HTC10 and HTC18 was found during in vitro gastrointestinal digestion. The three bioactive compounds loaded in OGEs showed high bioaccessibility values (∼84%) at the end of digestion, regardless their chain length and hydrophobicity. These OGEs designed as fat replacers showed a great potential for vehiculation of both hydrophilic and lipophilic compounds.

[Development of mechanical ventilators in Chile. Chronicle of the initiative "Un Respiro para Chile"]. / Desarrollo de ventiladores mecánicos en Chile. Crónica de la iniciativa "Un Respiro para Chile", durante la primera ola de la pandemia COVID-19.

At the beginning of the COVID-19 pandemic in Chile, in March 2020, a projection indicated that a significant group of patients with pneumonia would require admission to an Intensive Care Unit and connection to a mechanical ventilator. Therefore, a paucity of these devices and other supplies was predicted. The initiative "Un respiro para Chile" brought together many people and institutions, public and private. In the course of three months, it allowed the design and building of several ventilatory assistance devices, which could be used in critically ill patients.

Survey of Nurses' Experiences Applying The Joint Commission's Medication Management Titration Standards.

BACKGROUND: Critical care nurses titrate continuous infusions of medications to achieve clinical end points. In 2017, The Joint Commission (TJC) placed restrictions on titration practice, decreasing nurses' autonomous decision-making. OBJECTIVES: To describe the practice and perceptions of nurses regarding the 2017 TJC accreditation/regulatory standards for titration of continuous medication infusions. METHODS: A survey of nurses' experiences titrating continuous medication infusions was developed, validated, and distributed electronically to members of the American Association of Critical-Care Nurses. RESULTS: The content validity index for the survey was 1.0 for relevance and 0.95 for clarity. A total of 781 nurses completed the survey; 625 (80%) perceived titration standards to cause delays in patient care, and 726 (93%) experienced moral distress (mean [SD], 4.97 [2.67]; scale, 0-10). Among respondents, 33% could not comply with titration orders, 68% reported suboptimal care resulting from pressure to comply with orders, 70% deviated from orders to meet patient needs, and 84% requested revised orders to ensure compliance. Suboptimal care and delays in care significantly and strongly (regression coefficients ≥0.69) predicted moral distress. CONCLUSIONS: Critical care nurses perceive TJC medication titration standards to adversely impact patient care and contribute to moral distress. The improved 2020 updates to the standards do not address delays and inability to comply with orders, leading to moral distress. Advocacy is indicated in order to mitigate unintended consequences of TJC medication management titration standards.

Margarines: Historical approach, technological aspects, nutritional profile, and global trends.

Margarines are an expanding market worldwide due to large-scale commercial, lower cost, growth of bakery and confectionery markets, and seasonal independence. The fatty acid composition, solid fat content, consistency, and melting point of the fats used in margarine determine their functional properties. Due to its proven association with increased risk of cardiovascular diseases, the recommendations of the World Health Organization and the enactment of laws in several countries to eliminate industrially produced trans fatty acids (TFA) have resulted in the prohibition or progressive reduction in the use of partially hydrogenated fat. However, issues related to high levels of TFA and saturated fatty acids still constitute a challenge in the formulation of this product category. Current trends on margarine production addition of phytosterols, non-lipid components, organogels, and new interesterified fat bases are reviewed. This review aims to present a historical view and the technological evolution of margarines, including their production processes, formulations, and physical and nutritional characteristics, as well as legislation, and main trends.

Oleogel-based emulsions: Concepts, structuring agents, and applications in food.

This review discusses the application of oleogel technology in emulsified systems. In these systems of mimetic fats, water-in-oil or oil-in-water emulsions can be obtained, but, here, we cover emulsions with an oil continuous phase in detail. Depending on the percentage of water added to the oleogels, systems with different textures and rheological properties can be developed. These properties are affected by the characteristics and concentration of the added components and emulsion preparation methods. In addition, some gelators exhibit interfacial properties, resulting in more stable emulsions than those of conventional emulsions. Oleogel-based emulsion are differentiated by continuous and dispersed phases and the structuring/emulsification components. Crucially, these emulsions could be applied by the food industry for preparing, for example, meat products and margarines, as well as by the cosmetics industry. We present the different processes of emulsion elaboration, the main gelators used, the influence of the water content on the structuring of water-in-oleogel emulsions, and the structuring mechanisms (Pickering, network, and combined Pickering and network stabilization). Finally, we highlight the applications of these systems as alternatives for reducing processed food lipid content and saturated fat levels.

Organogels in low-fat and high-fat margarine: A study of physical properties and shelf life.

This study aimed to investigate the effect of the addition of organogels in low-fat and high-fat margarines during storage. Margarine formulations were made using water: oil ratios of 65:35 and 40:60 (w/w), and a lipid phase composed of organogel made with soybean oil, candelilla wax, fully hydrogenated palm oil, and mononoacylglycerols. The thermal stability, particle size, consistency, peroxide index, oil exudation, and microstructure of the margarines were evaluated for six months of storage. All margarines showed thermal stability at 35 °C, with no physical destabilization during the period studied. Both low-fat and high-fat margarines presented similar particle size distribution, with d3.3 around units of 5 µm. The peroxide index of the margarines ranged from 1.27 to 5.97 meq O2/Kg after six months of storage. High-fat margarines showed greater hardness and lower spreadability. The amount of water added to the formulations affected the stability, particle size, and texture of the margarines. It was possible to produce margarines with different fat contents and greater health appeal. The margarines with 60% and 35% fat exhibited 12.00 and 8.03% SFA; 32.63 and 18.20% PUFA; and 14.37 and 8.20% MUFA, respectively.

Identificación y Manejo del Gatillaje Reverso Utilizando la Gráfica Ventilatoria / Identifying and Managing of Reverse Triggering using Waveform Analysis

El gatillaje reverso es un tipo de asincronía paciente ventilador, potencialmente injuriosa, que se presenta en un gran porcentaje de pacientes ventilados mecánicamente. El gatillaje reverso es causado por la insuflación pulmonar pasiva por parte del ventilador mecánico, lo que genera una contracción diafragmática refleja. Su identificación y manejo, mediante el análisis de la gráfica ventilatoria, presenta un gran desafío para los profesionales de la salud que trabajan en Unidades de Cuidados Intensivos, debido a la gran dificultad para diagnosticarla correctamente si no se utilizan sistemas de monitorización como presión esofágica y/o la actividad eléctrica del diafragma. El objetivo de esta revisión es describir las estrategias para identificar y resolver el gatillaje reverso a partir de la evidencia científica aparecida en los últimos años.

Reverse triggering is a potentially injurious type of ventilator asynchrony (VPA) that occurs in a large percentage of mechanically ventilated patients. Reverse triggering is caused by passive lung insufflation by the mechanical ventilator, which generates a reflex diaphragmatic contraction. Its identification and management, through the analysis of the ventilatory graphics, is a great challenge for health-professionals, who work in Intensive Care Units, due to the great difficulty of correctly diagnosing it if monitoring systems such as esophageal pressure and / or the electrical activity of the diaphragm are not used. The objective of this review is to describe the strategies to identify and resolve the reverse trigger, based on the scientific evidence that has appeared in recent years.

Estimation of changes in cyclic lung strain by electrical impedance tomography: Proof-of-concept study.

RATIONALE: Cyclic strain may be a determinant of ventilator-induced lung injury. The standard for strain assessment is the computed tomography (CT), which does not allow continuous monitoring and exposes to radiation. Electrical impedance tomography (EIT) is able to monitor changes in regional lung ventilation. In addition, there is a correlation between mechanical deformation of materials and detectable changes in its electrical impedance, making EIT a potential surrogate for cyclic lung strain measured by CT (StrainCT ). OBJECTIVES: To compare the global StrainCT with the change in electrical impedance (ΔZ). METHODS: Acute respiratory distress syndrome patients under mechanical ventilation (VT 6 mL/kg ideal body weight with positive end-expiratory pressure 5 [PEEP 5] and best PEEP according to EIT) underwent whole-lung CT at end-inspiration and end-expiration. Biomechanical analysis was used to construct 3D maps and determine StrainCT at different levels of PEEP. CT and EIT acquisitions were performed simultaneously. Multilevel analysis was employed to determine the causal association between StrainCT and ΔZ. Linear regression models were used to predict the change in lung StrainCT between different PEEP levels based on the change in ΔZ. MAIN RESULTS: StrainCT was positively and independently associated with ΔZ at global level (P < .01). Furthermore, the change in StrainCT (between PEEP 5 and Best PEEP) was accurately predicted by the change in ΔZ (R2 0.855, P < .001 at global level) with a high agreement between predicted and measured StrainCT . CONCLUSIONS: The change in electrical impedance may provide a noninvasive assessment of global cyclic strain, without radiation at bedside.

Efecto del Flujo Operativo de la Cánula Nasal de Alto Flujo sobre el Rendimiento en la Entrega de Humedad / Effect of Operational Flow of the High Flow Nasal Cannula on Moisture Delivery Performance

Introducción: La canula nasal de alto flujo (CNAF) corresponde a un sistema de oxigenoterapia capaz de aplicar un flujo de gas de hasta 60 L/min a través de cánulas nasales. Este sistema es tolerable por el paciente debido a que el gas inspirado se encuentra calefaccionado y humidificado (temperatura de 34 ­ 37ºC, entregando una humedad relativa de 100%). El uso de este equipo es cada vez mayor, especialmente en el manejo de pacientes con falla respiratoria hipoxémica. Sin embargo no hay claridad del nivel de humedad que entrega, especialmente a altos flujos. Objetivo: Determinar el aporte real de humedad entregado por la CNAF a distintos flujos de operación. Métodos: Estudio in vitro, donde se utilizó un equipo de CNAF marca Fisher & Paykel Healthcare, modelo AIRVO®. Las mediciones de humedad relativa (H.R.) y temperatura se realizaron en una cámara ambiental de acrílico donde se conectó la cánula nasal. Para la medición de H.R. y temperatura se utilizó un higrómetro digital (Marca Veto®, Italia). Cada medición requirió un tiempo de 30 minutos para lograr un valor estable dentro de la cámara ambiental. Se realizaron mediciones a flujos de 15, 30, 40 y 50 LPM. Resultados: Las mediciones se realizaron a temperatura ambiental de 21,8 ºC y a una humedad relativa de 39%. Para un flujo programado en el equipo de 15 LPM y temperatura de 37ºC, se logra en la cámara ambiental una temperatura de 28,5ºC, con una humedad relativa de 95%. Para un flujo programado de 30 LPM y temperatura de 37ºC, se logra en la cámara ambiental una temperatura de 29,8ºC, con una humedad relativa de 97%. Para flujos operativos de 40 y 50 LPM, la temperatura y humedad relativa generadas fueron similares (HR 97% y 30ºC). Conclusiones: La temperatura entregada por el equipo de CNAF fue menor a la programada, pero mantuvo una alta tasa de HR.

Introduction: The high flow nasal cannula (HFNC) is an oxygen therapy system capable of applying a gas flow of up to 80 Lmin-1 through nasal cannulas. This system is tolerable by the patient due to the fact that the inspired gas is heated and humidified (temperature of 34 ­ 37ºC, delivering a relative humidity of 100%). The use of this equipment is increasing, especially in the management of patients with hypoxemic respiratory failure. However, there is no clarity on the level of humidity it delivers, especially at high flows. Objective: To determine the real humidity delivered by the CNAF to different operating flows. Methods: In vitro study. A Fisher & Paykel® CNAF equipment, AIRVO model, was used. Relative humidity (R.H.) and temperature measurements were performed in an acrylic environmental chamber where the nasal cannula was connected. For the measurement of H.R. and temperature, a digital hygrometer (Veto® Brand, Italy) was used. Each measurement required a time of 30 minutes to achieve a stable value. Measurements were made at flows of 15, 30, 40 and 50 Lmin-1. Results: Measurements were made at an ambient temperature of 21.8 ºC and a relative humidity of 39%. For a flow programmed in the equipment of 15 Lmin-1 and a temperature of 37ºC, a temperature of 28.5ºC is achieved in the environmental chamber, with a relative humidity of 95%. For a programmed flow of 30 Lmin-1 and a temperature of 37ºC, a temperature of 29.8ºC is achieved in the environmental chamber, with a relative humidity of 97%. For operating flows of 40 and 50 Lmin-1, the temperature and relative humidity generated were similar (RH 97% and 30ºC). Conclusions: The temperature delivered by the CNAF team was lower than programmed, but it maintained a high RH rate.

A Model of Queer STEM Identity in the Workplace.

Science, technology, engineering, and mathematics (STEM) fields are often stereotyped as spaces in which personal identity is subsumed in the pursuit of a single-minded focus on objective scientific truths, and correspondingly rigid expectations of gender and sexuality are widespread. This paper describes findings from a grounded theory inquiry of how queer individuals working in STEM fields develop and navigate personal and professional identities. Through our analysis, we identified three distinct but related processes of Defining a queer gender and/or sexual identity, Forming an identity as a STEM professional, and Navigating identities at work. We found that heteronormative assumptions frequently silence conversations about gender and sexuality in STEM workplaces and result in complicated negotiations of self for queer professionals. This analysis of the personal accounts of queer students, faculty, and staff in STEM reveals unique processes of identity negotiation and elucidates how different social positioning creates challenges and opportunities for inclusivity.