RESUMEN. Objetivo:Presentar la evidencia científica más reciente referente a la definición, diagnóstico y consecuencias de morbilidad extrema en obstetricia (MEO). Metodología de búsqueda: Búsqueda en PubMed, The Cochrane Library, OVID, Science Direct, Google Académico, Artemisa, LILACS e Imbiomed de artículos publicados en inglés y español entre los años 2005 a 2018 con las siguientes palabras clave: severe maternal morbidity, near miss morbidity, severe acute maternal morbidity, obstetric near miss and maternal near miss. Se excluyeron estudios cualitativos. Resultados: La MEO (o near miss) se refiere a cualquier complicación aguda que puede presentarse en el embarazo, labor o hasta seis semanas después de haber concluido el embarazo, estas complicaciones ponen en riesgo la vida de la madre, pero no resulta en su muerte. Los indicadores de MEO fueron desarrollados con base a la incidencia y presencia de trastornos hemorrágicos, hipertensivos y otras alteraciones sistémicas y condiciones maternas graves que pueden tener un impacto en la salud de la madre. En la actualidad, se sugiere que el estudio de los indicadores de MEO son de más utilidad que los de muerte materna. Conclusiones: El ejercicio de la práctica médica con base en la mejor evidencia científica, el estudio y la mejora de la calidad de la práctica clínica, de la planificación familiar, la asesoría prenatal y los programas hospitalarios son estrategias que permitirán ayudar a disminuir los casos de MEO. ABSTRACT. Objective: To provide the most recent scientific evidence about definitions, diagnosis and consequences of severe maternal morbidity (SMM). Research methodology:We searched databases in PubMed, The Cochrane Library, OVID, Science Direct, Google Scholar, Artemisa, LILACS and Imbiomed from 2005 to 2018 with the following keywords: severe maternal morbidity, near miss morbidity, severe acute maternal morbidity, obstetric near miss and maternal near miss. The search was restricted to articles written in the English and Spanish language and published from 2005 to 2018. Qualitative studies were excluded. Results: SMM or maternal near miss event refers to any acute obstetric complication that immediately threatens a woman's survival but does not result in her death either by chance or because of hospital care she receives during pregnancy, labor or within six weeks of termination of pregnancy. The indicators for SMM were developed and based on the incidence and presence of hemorrhagic disorders, hypertensive disorders, other systemic disorders and severe maternal conditions which could have an impact on maternal health. Nowadays it is suggested that the study of indicators for SMM is a more useful indicator of obstetric care than mortality. Conclusions: Use of best evidence-based practices, studying and improving the effectiveness and quality of clinical practice, family planning, prenatal check-up, and hospital obstetric care programs are strategies that could help to reduce cases of SMM.

In 1967, Ashbaugh et al. published in the Lancet the description of a new entity, for which they coined the name "adult respiratory distress syndrome". On that article, they thoroughly described 12 patients who had respiratory distress with bilateral pulmonary infiltrates and oxygen therapy-refractory hypoxemia. For its management, emphasis was made on the importance of intubation and mechanical ventilation with positive end-expiratory pressure. At 50 years of its first publication, great advances on the knowledge of this condition have been achieved, which has influenced on patient management and survival. To celebrate this 50th anniversary, the National Academy of Medicine of Mexico organized a symposium with the purpose to spread the knowledge about this condition, recognize the researchers who made the original description and those who over the course of 50 years of history have contributed to its better understanding. The symposium addressed the topics of lung-kidney interaction, molecular bases of the disease and therapeutic advances.

Conflicto de intereses: los autores declaran no tener ningún tipo de conflicto de intereses.

In 1967, Ashbaugh et al. published in the Lancet the description of a new entity, for which they coined the name "adult respiratory distress syndrome". On that article, they thoroughly described 12 patients who had respiratory distress with bilateral pulmonary infiltrates and oxygen therapy-refractory hypoxemia. For its management, emphasis was made on the importance of intubation and mechanical ventilation with positive end-expiratory pressure. At 50 years of its first publication, great advances on the knowledge of this condition have been achieved, which has influenced on patient management and survival. To celebrate this 50 th anniversary, the National Academy of Medicine of Mexico organized a symposium with the purpose to spread the knowledge about this condition, recognize the researchers who made the original description and those who over the course of 50 years of history have contributed to its better understanding. The symposium addressed the topics of lung-kidney interaction, molecular bases of the disease and therapeutic advances.