Evaluation of the classifications of severity in acute respiratory distress syndrome in childhood by the Berlin Consensus and the Pediatric Acute Lung Injury Consensus Conference.

OBJECTIVE: To compare two methods for defining and classifying the severity of pediatric acute respiratory distress syndrome: the Berlin classification, which uses the relationship between the partial pressure of oxygen and the fraction of inspired oxygen, and the classification of the Pediatric Acute Lung Injury Consensus Conference, which uses the oxygenation index. METHODS: This was a prospective study of patients aged 0 - 18 years with a diagnosis of acute respiratory distress syndrome who were invasively mechanically ventilated and provided one to three arterial blood gas samples, totaling 140 valid measurements. These measures were evaluated for correlation using the Spearman test and agreement using the kappa coefficient between the two classifications, initially using the general population of the study and then subdividing it into patients with and without bronchospasm and those with and without the use of neuromuscular blockers. The effect of these two factors (bronchospasm and neuromuscular blocking agent) separately and together on both classifications was also assessed using two-way analysis of variance. RESULTS: In the general population, who were 54 patients aged 0 - 18 years a strong negative correlation was found by Spearman's test (ρ -0.91; p < 0.001), and strong agreement was found by the kappa coefficient (0.62; p < 0.001) in the comparison between Berlin and Pediatric Acute Lung Injury Consensus Conference. In the populations with and without bronchospasm and who did and did not use neuromuscular blockers, the correlation coefficients were similar to those of the general population, though among patients not using neuromuscular blockers, there was greater agreement between the classifications than for patients using neuromuscular blockers (kappa 0.67 versus 0.56, p < 0.001 for both). Neuromuscular blockers had a significant effect on the relationship between the partial pressure of oxygen and the fraction of inspired oxygen (analysis of variance; F: 12.9; p < 0.001) and the oxygenation index (analysis of variance; F: 8.3; p = 0.004). CONCLUSION: There was a strong correlation and agreement between the two classifications in the general population and in the subgroups studied. Use of neuromuscular blockers had a significant effect on the severity of acute respiratory distress syndrome.

Host-Response Subphenotypes Offer Prognostic Enrichment in Patients With or at Risk for Acute Respiratory Distress Syndrome.

OBJECTIVES: Classification of patients with acute respiratory distress syndrome into hyper- and hypoinflammatory subphenotypes using plasma biomarkers may facilitate more effective targeted therapy. We examined whether established subphenotypes are present not only in patients with acute respiratory distress syndrome but also in patients at risk for acute respiratory distress syndrome (ARFA) and then assessed the prognostic information of baseline subphenotyping on the evolution of host-response biomarkers and clinical outcomes. DESIGN: Prospective, observational cohort study. SETTING: Medical ICU at a tertiary academic medical center. PATIENTS: Mechanically ventilated patients with acute respiratory distress syndrome or ARFA. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We performed longitudinal measurements of 10 plasma biomarkers of host injury and inflammation. We applied unsupervised latent class analysis methods utilizing baseline clinical and biomarker variables and demonstrated that two-class models (hyper- vs hypoinflammatory subphenotypes) offered improved fit compared with one-class models in both patients with acute respiratory distress syndrome and ARFA. Baseline assignment to the hyperinflammatory subphenotype (39/104 [38%] acute respiratory distress syndrome and 30/108 [28%] ARFA patients) was associated with higher severity of illness by Sequential Organ Failure Assessment scores and incidence of acute kidney injury in patients with acute respiratory distress syndrome, as well as higher 30-day mortality and longer duration of mechanical ventilation in ARFA patients (p < 0.0001). Hyperinflammatory patients exhibited persistent elevation of biomarkers of innate immunity for up to 2 weeks postintubation. CONCLUSIONS: Our results suggest that two distinct subphenotypes are present not only in patients with established acute respiratory distress syndrome but also in patients at risk for its development. Hyperinflammatory classification at baseline is associated with higher severity of illness, worse clinical outcomes, and trajectories of persistently elevated biomarkers of host injury and inflammation during acute critical illness compared with hypoinflammatory patients. Our findings provide strong rationale for examining treatment effect modifications by subphenotypes in randomized clinical trials to inform precision therapeutic approaches in critical care.

Reclassifying Acute Respiratory Distress Syndrome.

RATIONALE: The ratio of PaO2 to FiO2 (P/F) defines acute respiratory distress syndrome (ARDS) severity and suggests appropriate therapies. OBJECTIVES: We investigated 1) whether a 150-mm-Hg P/F threshold within the range of moderate ARDS (100-200 mm Hg) would define two subgroups that were more homogeneous; and 2) which criteria led the clinicians to apply extracorporeal membrane oxygenation (ECMO) in severe ARDS. METHODS: At the 150-mm-Hg P/F threshold, moderate patients were split into mild-moderate (n = 50) and moderate-severe (n = 55) groups. Patients with severe ARDS (FiO2 not available in three patients) were split into higher (n = 63) and lower (n = 18) FiO2 groups at an 80% FiO2 threshold. MEASUREMENTS AND MAIN RESULTS: Compared with mild-moderate ARDS, patients with moderate-severe ARDS had higher peak pressures, PaCO2, and pH. They also had heavier lungs, greater inhomogeneity, more noninflated tissue, and greater lung recruitability. Within 84 patients with severe ARDS (P/F < 100 mm Hg), 75% belonged to the higher FiO2 subgroup. They differed from the patients with severe ARDS with lower FiO2 only in PaCO2 and lung weight. Forty-one of 46 patients treated with ECMO belonged to the higher FiO2 group. Within this group, the patients receiving ECMO had higher PaCO2 than the 22 non-ECMO patients. The inhomogeneity ratio, total lung weight, and noninflated tissue were also significantly higher. CONCLUSIONS: Using the 150-mm-Hg P/F threshold gave a more homogeneous distribution of patients with ARDS across the severity subgroups and identified two populations that differed in their anatomical and physiological characteristics. The patients treated with ECMO belonged to the severe ARDS group, and almost 90% of them belonged to the higher FiO2 subgroup.

Classifying Acute Respiratory Distress Syndrome Severity: Correcting the Arterial Oxygen Partial Pressure to Fractional Inspired Oxygen at Altitude.

In the well-known Berlin definition of acute respiratory distress syndrome (ARDS), there is a recommended adjustment for arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FIO2) at altitude, but without a reference as to how it was derived.

Acute respiratory distress syndrome in patients with and without diffuse alveolar damage: an autopsy study.

OBJECTIVE: To demonstrate that among patients with acute respiratory distress syndrome (ARDS), the presence of diffuse alveolar damage (DAD) at histological examination, as compared to its absence, defines a specific subphenotype. METHODS: We studied 149 patients who died in our ICU with the clinical diagnosis of ARDS according to the Berlin Definition (BD) and who had autopsy examination. We compared the change over time of different clinical variables in patients with (n = 49) and without (n = 100) DAD. A predictive model for the presence of DAD was developed and validated in an independent cohort of 57 patients with ARDS and postmortem examination (21 of them with DAD). RESULTS: Patients with DAD, as compared to patients without DAD, had a lower PaO2/FiO2 ratio and dynamic respiratory system compliance, and a higher SOFA score and INR, and were more likely to die of hypoxemia and less likely to die of shock. In multivariate analysis, variables associated with DAD [odds ratio, 95% confidence interval (CI)] were PaO2/FiO2 ratio [0.988 (0.981-0.995)], dynamic respiratory system compliance [0.937 (0.892-0.984)] and age [0.972 (0.946-0.999)]. Areas under the ROC curve (95 % CI) for the classification of DAD using the regression model or the BD were, respectively, 0.74 (0.65-0.82) and 0.64 (0.55-0.72) (p = 0.03). In the validation cohort, the areas under the ROC curve for the diagnosis of DAD were 0.73 (0.56-0.90) and 0.67 (0.54-0.81) for the regression model and the BD, respectively. CONCLUSIONS: The presence of DAD appears to define a specific subphenotype in patients with ARDS. Targeting patients with DAD within the population of patients with the clinical diagnosis of ARDS might be appropriate to find effective therapies for this condition.

Síndrome de angústia respiratória aguda após Berlim / Acute respiratory distress syndrome after Berlin

As definições de Berlim tiveram o objetivo de aumentar a acurácia diagnóstica frente à Síndrome de Angústia Respiratória Aguda (SARA), principalmente no que diz respeito à sua estratificação de gravidade e ao seu prognóstico, progressivamente pior, associado a esta classificação. Esta distinção permitiu, inclusive que a abordagem terapêutica fosse aplicada de maneira mais oportuna e adequada, no momento da detecção da SARA grave, como, por exemplo, o uso da posição prona. Entretanto, ainda críticas existem sobre essas definições, que determinam incertezas relativas à reprodutibilidade, relacionada à estratégia ventilatória inicial pré diagnóstico, e à sua validade preditiva para letalidade. Portanto, essa revisão aborda esses questionamentos e apresenta possíveis melhorias futuras na sensibilidade e especificidade diagnósticas dessa síndrome de elevada letalidade em nosso país...

Berlin definition was intended to increase the diagnostic accuracy upon the Acute Respiratory Distress Syndrome (ARDS), particularly with regard to its stratification of severity and prognosis, progressively worse, associated with this classification. This distinction has allowed even that the therapeutic approach was applied in a more timely and adequate way at the time of detection of severe ARDS, such as, for instance, the use of the prone position. However, there is still criticism about these settings that determine uncertainties regarding the reproducibility, related to the initial ventilatory strategy before this diagnosis, and its predictive validity for mortality. Therefore, this review addresses these questions and presents possible future improvements in the diagnostic sensitivity and specificity of this highly lethal syndrome in our country...

What is the future of acute respiratory distress syndrome after the Berlin definition?

PURPOSE OF REVIEW: To analyze recently published articles in the medical literature that studied distinct aspects of adult patients with acute respiratory distress syndrome (ARDS) after the new Berlin definition introduced in 2012. RECENT FINDINGS: The degree of ARDS severity according to this new classification correlated well with extravascular lung water index, pulmonary vascular permeability index and the finding of diffuse alveolar damage on autopsy. The new possibility of bedside echocardiographic evaluation of biventricular cardiac function is indicating the necessity of including a subgroup of severity of patients with right ventricular dysfunction. High-resolution CT evaluation showed that signs of pulmonary fibroproliferation in early ARDS predict increased ventilator dependency, multiple organ failure and mortality. The median development of ARDS 1 or 2 days after hospital admission emphasizes the need for ARDS intrahospital prevention, especially protective ventilation in non-ARDS patients. The better outcome with the use of prone position in patients with PaO2/FIO2 below 150 recently observed questioned the Berlin definition thresholds to decide the future best treatment strategies according to the proposed degree of severity of the syndrome. SUMMARY: The impact of the Berlin definition of ARDS on the incidence, better treatment stratification and mortality ratio of ARDS is still to be determined.

Evolução temporal das definições de síndrome do desconforto respiratório agudo / Temporal evolution of acute respiratory distress syndrome definitions

OBJETIVO: revisar a evolução das definições de síndrome do desconforto respiratório agudo e apresentar a proposta atual para a mesma. FONTES DOS DADOS: revisão bibliográfica e seleção de publicações mais relevantes sobre as definições de síndrome do desconforto respiratório agudo, utilizando a base de dados MEDLINE®/PubMed® Resources Guide (últimos dez anos), além da inclusão dos artigos mais importantes (artigos clássicos) que descrevem a evolução da doença. SÍNTESE DOS DADOS: revisão incluiu os seguintes tópicos: introdução; importância da definição; descrição do primeiro critério diagnóstico e das definições utilizadas subsequentemente, como o escore de lesão pulmonar aguda, definição da Conferência de Consenso Americana- Europeia e suas limitações, descrição da definição de Delphi e seus problemas; acurácia das definições citadas e descrição da definição mais recente (Definição de Berlim) e suas limitações; e importância prática da nova definição. CONCLUSÕES: a síndrome do desconforto respiratório agudo é uma doença grave, que consiste em um contínuo desafio diagnóstico e terapêutico. A evolução das definições utilizadas para descrever a doença evidencia que estudos são necessários para validar a definição atual, principalmente em pediatria, onde os dados são muito escassos.

OBJECTIVE: to review the evolution of acute respiratory distress syndrome (ARDS) definitions and present the current definition for the syndrome. DATA SOURCE: a literature review and selection of the most relevant articles on ARDS definitions was performed using the MEDLINE®/PubMed® Resource Guide database (last ten years), in addition to including the most important articles (classic articles) that described the disease evolution. DATA SYNTHESIS: the review included the following subjects: introduction; importance of definition; description of the first diagnostic criterion and subsequently used definitions, such as acute lung injury score; definition by the American-European Consensus Conference, and its limitations; description of the definition by Delphi, and its problems; accuracy of the aforementioned definitions; description of most recent definition (the Berlin definition), and its limitations; and practical importance of the new definition. CONCLUSIONS: ARDS is a serious disease that remains an ongoing diagnostic and therapeutic challenge. The evolution of definitions used to describe the disease shows that studies are needed to validate the current definition, especially in pediatrics, where the data are very scarce.

Temporal evolution of acute respiratory distress syndrome definitions.

OBJECTIVE: to review the evolution of acute respiratory distress syndrome (ARDS) definitions and present the current definition for the syndrome. DATA SOURCE: a literature review and selection of the most relevant articles on ARDS definitions was performed using the MEDLINE®/PubMed® Resource Guide database (last ten years), in addition to including the most important articles (classic articles) that described the disease evolution. DATA SYNTHESIS: the review included the following subjects: introduction; importance of definition; description of the first diagnostic criterion and subsequently used definitions, such as acute lung injury score; definition by the American-European Consensus Conference, and its limitations; description of the definition by Delphi, and its problems; accuracy of the aforementioned definitions; description of most recent definition (the Berlin definition), and its limitations; and practical importance of the new definition. CONCLUSIONS: ARDS is a serious disease that remains an ongoing diagnostic and therapeutic challenge. The evolution of definitions used to describe the disease shows that studies are needed to validate the current definition, especially in pediatrics, where the data are very scarce.

The new definition for acute lung injury and acute respiratory distress syndrome: is there room for improvement?

PURPOSE OF REVIEW: To review the new (Berlin) definition of the acute respiratory distress syndrome (ARDS) and to propose potential improvements. RECENT FINDINGS: The Berlin definition resulted in the following modifications: a criterion of less than 7 days was used to define acute onset; the requirement of pulmonary artery wedge pressure was removed. Clinical judgment for characterizing hydrostatic pulmonary edema suffices, unless there is no apparent ARDS risk factor, in which case an objective evaluation is required; the category of acute lung injury was removed, and ARDS was divided into three categories of severity based on the P/F ratio - mild (from 201 to 300), moderate (from 101 to 200), and severe (≤100  mmHg). A positive end-expiratory pressure value of at least 5  cm H(2)O became required for the diagnosis of ARDS. In this review, we propose that both the use of P/F ratio after some stabilization (first 24  h) and the use of compliance stratified at 0.4  ml/cm H(2)O/kg ideal body weight might improve the stratification of patients. SUMMARY: The Berlin definition brought improvement and simplification over the previous definitions. The use of data over the first 24  h to reclassify the severity of the disease and the use of compliance to stratify each oxygenation category might further improve the definition.

Nueva definición de Berlín de síndrome de distrés respiratorio agudo / New definition of Berlin for acute respiratory distress syndrome

Desde la definición de síndrome de distrés respiratorio agudo (SDRA) realizada por Ashbaugh y cols. en 1967,varias modificaciones fueron propuestas hasta 1994 en donde la Conferencia del Consenso Americano-Europeo propuso una nueva definición que ha perdurado casi 2 décadas y ha sido operativa para la investigación y de utilidad para los clínicos. Sin embargo, varios autores han sido crítico de ésta, encontrando varias deficiencias entre lasque se encuentra la baja especificidad de esta definición (51 por ciento). En el año 2011, un panel de expertos internacional desarrolló la nueva definición de Berlín de SDRA, la cual se centro en la viabilidad, fiabilidad, validez, y la evaluación objetiva de su rendimiento. Ésta, incorpora varias modificaciones entre las cuales destaca la categorización del SDRA en 3 niveles (leve, moderado y grave) de acuerdo al grado de hipoxemia que presenta el paciente con un mínimo de uso de PEEP (>5 cm H2O) y elimina el concepto de Daño Pulmonar agudo o ALI. Este documento analiza la nueva definición de SDRA.

From the definition of acute respiratory distress syndrome (ARDS) by Ashbaugh et al in 1967, several amendments were proposed until 1994 in which the American-European Consensus Conference proposed a new definition that has lasted almost 2 decades and has been operational for research and useful to clinicians. However, several authors have criticized adressing towards several weaknesses on it, including the low specificity of this definition (51 percent). In 2011, a panel of experts developed the Berlin Definition of ARDS, focusing on feasibility, reliability, validity, and objective evaluation of its performance. It incorporates several modifications among which the categorization of ARDS in 3 levels (mild, moderate and severe) according to the degree of hypoxemia in the patient with minimal use of PEEP (>5cm H2O) and eliminates the concept of acute lung injury (ALI). This paper discusses the new definition of ARDS.

Síndrome do Desconforto Respiratório Agudo: definição / Acute Respiratory Distress Syndrome: definition

A definição da síndrome do desconforto respiratório agudo (SDRA), simplificada pela Conferência Americana e Europeia de Consenso em SDRA de 1998, inclui a presença de infiltrado pulmonar bilateral, relação pressão parcial arterial de oxigênio/fração inspirada de oxigênio < 200 mmHg e pressão capilar pulmonar < 18 mmHg ou ausência de sinais de insuficiência cardíaca esquerda. Atualmente, o entendimento mais complexo da SDRA inclui sua análise mais detalhada pela tomografia de tórax e por outros métodos de imagem. A utilização de marcadores genéticos e biomarcadores plasmáticos e no lavado broncoalveolar antecipará o diagnóstico e o prognóstico de SDRA. A introdução de sistemas automáticos de diagnóstico e a análise de fatores de risco e de fatores prognósticos associados à SDRA ajudarão no entendimento mais aprofundado da doença para seu melhor tratamento e diminuição de suas taxas de mortalidade.

The definition of acute respiratory distress syndrome (ARDS) was simplified at the 1998 American-European Consensus Conference of 1998 and now includes the following: bilateral pulmonary infiltrates; arterial oxygen tension/fraction of inspired oxygen < 200 mmHg; and pulmonary capillary wedge pressure < 18 mmHg or no signs of left heart failure. Recently, tomography and other imaging methods have allowed the chest to be analyzed in greater detail, thereby leading to a more complex understanding of ARDS. The use of genetic markers and biomarkers in plasma and bronchoalveolar lavage could lead to earlier ARDS diagnosis, thereby improving prognosis. The introduction of automatic diagnostic screening, together with the analysis of risk factors and prognostic factors associated with the syndrome, will deepen the understanding of ARDS, improving treatment and potentially reducing the associated mortality rates.

Pulmonary and extrapulmonary acute respiratory distress syndrome: are they different?

PURPOSE OF REVIEW: Acute respiratory distress syndrome has been considered a morphologic and functional expression of lung injury caused by a variety of insults. Two distinct forms of acute respiratory distress syndrome/acute lung injury are described, because there are differences between pulmonary acute respiratory distress syndrome (direct effects on lung cells) and extrapulmonary acute respiratory distress syndrome (reflecting lung involvement in a more distant systemic inflammatory response). This article will focus on the differences in lung histology and morphology, respiratory mechanics, and response to ventilatory strategies and pharmacologic therapies in pulmonary and extrapulmonary acute respiratory distress syndrome. RECENT FINDINGS: Many researchers recognize that experimental pulmonary and extrapulmonary acute respiratory distress syndrome are not identical. In addition, clinical studies have described the detection of differences radiographically, functionally, and by analysis of the responses to therapeutic interventions (ventilatory strategies, positive end-expiratory pressure, prone position, drugs). However, there are contradictions among the different studies addressing these issues, which could be attributed to the fact that the distinction between pulmonary and extrapulmonary acute respiratory distress syndrome is not always clear and simple. Furthermore, there may be frequent overlapping in pathogenetic mechanisms and morphologic alterations. SUMMARY: The understanding of acute respiratory distress syndrome needs to take into account its origin. If each pathogenetic mechanism were to be considered, clinical management would be more precise, and probably the outcome could include real amelioration.

Comparison between cardiac output values measured by thermodilution and partial carbon dioxide rebreathing in patients with acute lung injury

CONTEXTO: A termodiluição, considerada técnica padrão para medida do débito cardíaco em pacientes graves, não é isenta de riscos relevantes. Faz-se necessário encontrar métodos alternativos não invasivos, automáticos, simples e acurados para monitorar o débito cardíaco à beira do leito. OBJETIVO: Comparar as medidas do débito cardíaco obtido com os métodos termodiluição e reinalação parcial de gás carbônico em pacientes com lesão pulmonar aguda em dois níveis de gravidade (índice de lesão pulmonar - LIS abaixo de 2,5 grupo A; e acima de 2,5, grupo B). TIPO DO ESTUDO: Comparativo, prospectivo, controlado. LOCAL: Unidades de Terapia Intensiva de dois hospitais-escola. MÉTODOS: Vinte pacientes acometidos de insuficiência respiratória aguda (PaO2/FiO2 < 300), sob ventilação pulmonar artificial, nos quais foram realizadas 294 medidas, 164 medidas no grupo A (n = 11) e 130 no grupo B (n = 9),variando de 14 a 15 medidas por paciente, foram estudados. Débito cardíaco foi medido com termodiluição e reinalação parcial de gás carbônico. RESULTADOS: A correlação entre os métodos estudados foi fraca no grupos A (r = 0,52, p < 0,001*) e no B: r = 0,47, p < 0,001*). A aplicação do teste de Bland-Altman permitiu evidenciar a discordância entre os métodos (grupo A: -0,9 ± 2,71 l/min; IC 95% = - 1,14 a -0,48; e grupo B: -1,75 ± 2,05 l/min (IC 95% = -2,11 a -1,4). A comparação dos resultados (testes t para grupos emparelhados e Mann-Whitney) obtidos nos grupos e entre os grupos de estudo revelou diferenças ( p = 0,00*, p < 0,05). DISCUSSAO: Erros em estimar o CaCO2 (conteúdo arterial de CO2) através da ETCO2 (CO2 de final de corrente) e situações de circulação hiperdinâmica associados a espaço morto e/ou shunt possivelmente expliquem nossos resultados. CONCLUSAO: Em pacientes com lesão pulmonar aguda, o débito cardíaco determinado pela reinalação parcial de gás carbônico difere dos valores medidos com termodiluição. Esta diferença se acentua com a maior gravidade da lesão pulmonar.

Síndrome de dificultad respiratoria del adulto: tratamiento y estrategia ventilatoria / Acute respiratory distress syndrome: therapeutic interventions and ventilatory strategy

El síndrome de dificultad respiratoria agudo responde a múltiples etiologías tales como sepsis, neumonía, peritonitis y trauma múltiple entre otras y es un proceso inflamatorio difuso y generalizado del pulmón. Su evolución depende de muchos factores que incluyen la severidad del cuadro clínico, la enfermedad fundamental y el desarrollo de fallo multiorgánico. A pesar de ser un proceso universal en el pulmón existen diferencias funcionales según se trate de un SDRA de curso primario (ej. Neumonía) o SDRA secundario (ej. Sepsis no pulmonar). Durante los últimos 20 años ha habido cambios fundamentales en las estrategias ventilatorias de estos pacientes. Esto tiene influencia fundamental en mejorar la PaO2 y se denominan estrategias de reclutamiento alveolar. En esta publicación sobre SDRA actualizamos los nuevos conocimientos fisiopatológicos de esta entidad como así también las estrategias ventilatorias que han demostrado tener impacto en la evolución de los pacientes con SDRA.

Síndrome de dificultad respiratoria del adulto: tratamiento y estrategia ventilatoria / Acute respiratory distress syndrome: therapeutic interventions and ventilatory strategy

El síndrome de dificultad respiratoria agudo responde a múltiples etiologías tales como sepsis, neumonía, peritonitis y trauma múltiple entre otras y es un proceso inflamatorio difuso y generalizado del pulmón. Su evolución depende de muchos factores que incluyen la severidad del cuadro clínico, la enfermedad fundamental y el desarrollo de fallo multiorgánico. A pesar de ser un proceso universal en el pulmón existen diferencias funcionales según se trate de un SDRA de curso primario (ej. Neumonía) o SDRA secundario (ej. Sepsis no pulmonar). Durante los últimos 20 años ha habido cambios fundamentales en las estrategias ventilatorias de estos pacientes. Esto tiene influencia fundamental en mejorar la PaO2 y se denominan estrategias de reclutamiento alveolar. En esta publicación sobre SDRA actualizamos los nuevos conocimientos fisiopatológicos de esta entidad como así también las estrategias ventilatorias que han demostrado tener impacto en la evolución de los pacientes con SDRA. (AU)

Randomización: ¿un juego de azar? / Randomization: a game of chance?

Los estudios randomizados representan una de las más elegantes soluciones para evitar las desinteligencias en la interpretación del efecto terapeútico en presencia de problemas complejos. Sin embargo los estudios randomizados son muy costosos, difíciles de implementar y algunas veces imposibles de realizar por enfrentar problemas bioéticos insolubles. Debido a ésto es quizás que solamente el 20 por ciento de las guías clínicas se basan en sus resultados. Se discuten además estudios randomizados en SDRA (AU)

Randomización: ¿un juego de azar? / Randomization: a game of chance?

Los estudios randomizados representan una de las más elegantes soluciones para evitar las desinteligencias en la interpretación del efecto terapeútico en presencia de problemas complejos. Sin embargo los estudios randomizados son muy costosos, difíciles de implementar y algunas veces imposibles de realizar por enfrentar problemas bioéticos insolubles. Debido a ésto es quizás que solamente el 20 por ciento de las guías clínicas se basan en sus resultados. Se discuten además estudios randomizados en SDRA

Síndrome de dificultad respiratoria aguda del adulto: enigma mortal (primera parte)

En agosto de 1967 Ausbaugh reportó el "síndrome de dificultad respiratoria aguda del adulto". Los primeros estudios demostraron que el edema pulmonar agudo que sufrían los pacientes afectados por el mismo, era ocasionado por un aumento de la permeabilidad capilar debida a múltiples lesiones en lamembrana alveolocapilar. Pronto se comprobó que en los pulmones se producía reclutamiento de neutrófilos, mediado por el complemento; estos liberaban elastasa, colagenasa y radicales de oxígeno que originaban la injuria pulmonar. En la última década varios investigadores responsabilizaron también a numerosos agentes mediadores de la inflamación: citoquinas, leucotrienos y tromboxano. A(2) Postularon entonces que el síndrome de dificultad respiratoria aguda del adulto, era en realidad, un proceso inflamatorio sistémico muy complejo, cuya secuencia de eventos patológicos permanece aún sin descifrar. por tal motivo han fallado todos los ensayos terapéuticos y la mortalidad a través del tiempo ha permanecido invariable: fallecen más del 60 por ciento de los pacientes a pesar del uso de sofisticados métodos de soporte respiratorio: presión positiva al final de la espirción-inversión de la relación ventilatoria. Contrario a lo que se pensaba, la mayoría de los pacientes no mueren de insuficiencia respiratoria sino de sepsis o de falla orgánica multisistémica. (MEDICAS UIS 1999;13:75-88).